From be9c9077cd62232f3a6ecac2a6c2d309cfb68545 Mon Sep 17 00:00:00 2001
From: p01ntov <278898977+p01ntov@users.noreply.github.com>
Date: Sat, 17 Oct 2026 13:56:35 +0300
Subject: [PATCH 01/13] G2: tessellate viewer path overlays in screen space

---
 crates/ui-egui/src/panels/viewer_overlays.rs | 152 ++++++++++++++++++-
 1 file changed, 146 insertions(+), 6 deletions(-)

diff --git a/crates/ui-egui/src/panels/viewer_overlays.rs b/crates/ui-egui/src/panels/viewer_overlays.rs
index 9117103d5..d0875941e 100644
--- a/crates/ui-egui/src/panels/viewer_overlays.rs
+++ b/crates/ui-egui/src/panels/viewer_overlays.rs
@@ -132,17 +132,52 @@ pub(crate) fn path_of(ectx: &EvalCtx, layer: LayerId, uid: u64) -> Option<PathIn
 /// The path on screen: `sp` through `m` and the viewer map, flattened, with the closing point
 /// repeated for a closed path.
 pub(crate) fn flatten(sp: &ShapePath, m: &Mat3, map: &ViewerMap) -> Vec<Pos2> {
-    let k = effectcraft_engine::render::kurbo_path(sp);
+    let mut k = effectcraft_engine::render::kurbo_path(sp);
+    // A path-space tolerance becomes visible corners when the viewer or a layer/group is
+    // magnified. Flatten affine paths in screen space so the error stays below half a point.
+    // Projective transforms must still map the flattened points: projecting Bezier control
+    // points would change the curve rather than just its tessellation.
+    let screen_space = m.is_affine();
+    if screen_space {
+        let z = f64::from(map.zoom);
+        k.apply_affine(kurbo::Affine::new([
+            m.0[0][0] * z,
+            m.0[1][0] * z,
+            m.0[0][1] * z,
+            m.0[1][1] * z,
+            m.0[0][2] * z + f64::from(map.origin.x),
+            m.0[1][2] * z + f64::from(map.origin.y),
+        ]));
+    }
+    if !k.is_finite() {
+        return Vec::new();
+    }
+    let bounds = k.control_box();
+    if [bounds.x0, bounds.y0, bounds.x1, bounds.y1].iter().any(|v| v.abs() > f64::from(f32::MAX)) {
+        return Vec::new();
+    }
+    // Bound subdivision work even for extreme finite scales from a malformed project. For
+    // ordinary on-screen paths the tolerance remains half a point.
+    let tolerance = (bounds.width().max(bounds.height()) / 1_000_000.0).max(0.5);
     let mut pts: Vec<Pos2> = vec![];
-    kurbo::flatten(k.iter(), 0.5, |el| match el {
+    kurbo::flatten(k.iter(), tolerance, |el| match el {
         kurbo::PathEl::MoveTo(q) | kurbo::PathEl::LineTo(q) => {
-            let c = m.apply(gv2(q.x, q.y));
-            pts.push(map.to_screen([c.x, c.y]));
+            let p = if screen_space {
+                egui::pos2(q.x as f32, q.y as f32)
+            } else {
+                let c = m.apply(gv2(q.x, q.y));
+                map.to_screen([c.x, c.y])
+            };
+            if p.is_finite() {
+                pts.push(p);
+            }
         }
         _ => {}
     });
-    if sp.closed && !pts.is_empty() {
-        pts.push(pts[0]);
+    if sp.closed
+        && let Some(first) = pts.first().copied()
+    {
+        pts.push(first);
     }
     pts
 }
@@ -679,6 +714,111 @@ mod tests {
         PathInfo { layer: LayerId(3), uid: 7, m: Mat3::IDENTITY, sp, is_mask: true, feather: Vec::new() }
     }
 
+    fn circle() -> ShapePath {
+        let r = 38.0;
+        let h = r * 0.552_284_749_830_793_6;
+        ShapePath {
+            vertices: vec![[0.0, -r], [r, 0.0], [0.0, r], [-r, 0.0]],
+            in_tangents: vec![[-h, 0.0], [0.0, -h], [h, 0.0], [0.0, h]],
+            out_tangents: vec![[h, 0.0], [0.0, h], [-h, 0.0], [0.0, -h]],
+            closed: true,
+            feather: Vec::new(),
+        }
+    }
+
+    /// Measure the actual screen-space error against dense samples of the original cubics,
+    /// independently of the tessellator's chosen subdivisions.
+    fn screen_error(sp: &ShapePath, m: &Mat3, map: &ViewerMap, points: &[Pos2]) -> f32 {
+        let mut worst = 0.0_f32;
+        for i in 0..sp.vertices.len() {
+            let Some(c) = segment(sp, i) else { continue };
+            for step in 0..=1024 {
+                let q = cubic(c[0], c[1], c[2], c[3], f64::from(step) / 1024.0);
+                let q = m.apply(gv2(q[0], q[1]));
+                let p = map.to_screen([q.x, q.y]);
+                let distance = points
+                    .windows(2)
+                    .map(|pair| {
+                        let a = pair[0];
+                        let v = pair[1] - a;
+                        let t = if v.length_sq() > 0.0 { ((p - a).dot(v) / v.length_sq()).clamp(0.0, 1.0) } else { 0.0 };
+                        p.distance(a + v * t)
+                    })
+                    .fold(f32::INFINITY, f32::min);
+                worst = worst.max(distance);
+            }
+        }
+        worst
+    }
+
+    #[test]
+    fn curve_overlay_stays_smooth_at_viewer_magnifications() {
+        let sp = circle();
+        let mut counts = Vec::new();
+        for zoom in [0.5, 1.0, 5.0] {
+            let map = ViewerMap { origin: egui::pos2(121.25, 210.5), zoom, comp: [640.0, 400.0], area: Rect::EVERYTHING };
+            let points = flatten(&sp, &Mat3::IDENTITY, &map);
+            let error = screen_error(&sp, &Mat3::IDENTITY, &map, &points);
+            assert!(error <= 0.51, "{zoom}x: {error} screen points from the curve");
+            assert_eq!(points.first(), points.last(), "closed paths keep their closing edge");
+            for v in &sp.vertices {
+                let anchor = map.to_screen(*v);
+                assert!(points.iter().any(|p| p.distance(anchor) < 0.001), "original vertex missing at {zoom}x");
+            }
+            counts.push(points.len());
+        }
+        assert!(counts[0] < counts[1] && counts[1] < counts[2], "tessellation follows visible curve size: {counts:?}");
+    }
+
+    #[test]
+    fn curve_overlay_accounts_for_nonuniform_layer_and_group_transforms() {
+        let sp = circle();
+        let layer = Mat3::translate(gv2(70.0, 50.0)) * Mat3::rotate_deg(27.0) * Mat3::scale(gv2(3.2, 0.8));
+        let group = Mat3::rotate_deg(-19.0) * Mat3::skew_deg(25.0, 11.0) * Mat3::scale(gv2(0.7, 2.5));
+        let m = layer * group;
+        for zoom in [0.5, 1.0, 5.0] {
+            let map = ViewerMap { origin: egui::pos2(121.25, 210.5), zoom, comp: [640.0, 400.0], area: Rect::EVERYTHING };
+            let points = flatten(&sp, &m, &map);
+            let error = screen_error(&sp, &m, &map, &points);
+            assert!(error <= 0.51, "{zoom}x transformed path: {error} screen points from the curve");
+        }
+    }
+
+    #[test]
+    fn open_overlay_preserves_its_transformed_endpoints() {
+        let sp = info(vec![[10.0, 20.0], [50.0, 60.0]], false).sp;
+        let m = Mat3::translate(gv2(70.0, 50.0)) * Mat3::rotate_deg(27.0) * Mat3::scale(gv2(3.2, 0.8));
+        let map = ViewerMap { origin: egui::pos2(121.25, 210.5), zoom: 5.0, comp: [640.0, 400.0], area: Rect::EVERYTHING };
+        let points = flatten(&sp, &m, &map);
+        assert_ne!(points.first(), points.last(), "an open path must not gain a closing edge");
+        for (point, vertex) in [points.first(), points.last()].into_iter().zip([sp.vertices.first(), sp.vertices.last()]) {
+            let q = m.apply(gv2(vertex.unwrap()[0], vertex.unwrap()[1]));
+            assert!(point.unwrap().distance(map.to_screen([q.x, q.y])) < 0.001);
+        }
+    }
+
+    #[test]
+    fn invalid_overlay_coordinates_are_not_tessellated() {
+        let sp = circle();
+        for zoom in [f32::NAN, f32::INFINITY] {
+            let map = ViewerMap { origin: Pos2::ZERO, zoom, comp: [640.0, 400.0], area: Rect::EVERYTHING };
+            assert!(flatten(&sp, &Mat3::IDENTITY, &map).is_empty());
+        }
+        let map = ViewerMap { origin: Pos2::ZERO, zoom: 5.0, comp: [640.0, 400.0], area: Rect::EVERYTHING };
+        assert!(flatten(&sp, &Mat3::scale(gv2(f64::INFINITY, 1.0)), &map).is_empty());
+    }
+
+    #[test]
+    fn extreme_finite_overlay_scales_keep_subdivision_bounded() {
+        let map = ViewerMap { origin: Pos2::ZERO, zoom: 5.0, comp: [640.0, 400.0], area: Rect::EVERYTHING };
+        let sp = circle();
+        let points = flatten(&sp, &Mat3::scale(gv2(1e12, 1e12)), &map);
+        assert!(!points.is_empty());
+        assert!(points.len() < 10_000, "extreme scales must not allocate millions of vertices");
+        assert!(points.iter().all(|p| p.is_finite()));
+        assert!(flatten(&sp, &Mat3::scale(gv2(1e300, 1e300)), &map).is_empty());
+    }
+
     /// #912: clicking the last vertex of an open path with the Pen resumes that path.
     #[test]
     fn pen_resumes_an_open_path_at_its_last_vertex() {

From 0ca3f72ac2175521c1a109dabb3f8a2242528709 Mon Sep 17 00:00:00 2001
From: becauseno7 <95076423+becauseno7@users.noreply.github.com>
Date: Fri, 30 Oct 2026 04:34:30 +0600
Subject: [PATCH 02/13] CC Bubbles: bubbles refract the layer's edge pixels on
 padded buffers too (#2024)

Refraction samples are clamped to the layer rectangle instead of the buffer, so a sample past the
layer's edge in a buffer with transparent padding (a half-resolution preview's, a text or shape
layer's) repeats the layer's edge pixels rather than reaching the pale colour that stands in for
transparent ones. Transparent pixels inside the layer still show it. Same bounds on the GPU path.

Re-pins the four half-resolution CC Bubbles golden hashes (aarch64 macOS); the full-resolution
ones are unchanged. Adds a CPU test and a GPU-vs-CPU parity test on padded buffers.
---
 crates/effects/src/lib.rs             |  2 +-
 crates/effects/src/sim.rs             |  2 +-
 crates/effects/src/sim/tests.rs       | 39 +++++++++++++++++++++++++++
 crates/effects/src/sim/weather.rs     | 14 +++++++++-
 crates/effects/tests/it/sim_golden.rs |  8 +++---
 crates/gpu/src/fx_sim.rs              |  1 +
 crates/gpu/src/shaders/fx_sim.wgsl    |  7 +++--
 crates/gpu/src/tests/fx_sim.rs        | 28 +++++++++++++++++++
 8 files changed, 92 insertions(+), 9 deletions(-)

diff --git a/crates/effects/src/lib.rs b/crates/effects/src/lib.rs
index 32e662fec..a5534bf86 100644
--- a/crates/effects/src/lib.rs
+++ b/crates/effects/src/lib.rs
@@ -117,7 +117,7 @@ pub use ocio::color_stabilizer_maps;
 // GPU effects, part B (3D Channel, Immersive Video, colour management, simulation render passes).
 pub use channel3d::{CRYPTO_LAYERS, CryptoAux, aux_point, crypto_aux_image, crypto_aux_image_with, id_color, selection_hashes};
 pub use ocio::{ColorOp, Straight, Tf, color_program};
-pub use sim::{Acc, Blob, Bubble, Post, Shape, Sprite, SpritePlan, Tint, bubble_list, drizzle_drops, mercury_blobs, sprite_plan};
+pub use sim::{Acc, Blob, Bubble, Post, Shape, Sprite, SpritePlan, Tint, bubble_list, bubble_sample_bounds, drizzle_drops, mercury_blobs, sprite_plan};
 pub use sim2::{
     CausticsSetup, FoamDisc, FoamEnv, FoamPlan, Piece, PiecePlan, PieceTex, PixelPlan, WavePlan, Waves, caustics_setup, foam_full_plan, piece_plan, pixel_plan,
     wave_world_plan,
diff --git a/crates/effects/src/sim.rs b/crates/effects/src/sim.rs
index 79a225f75..333549e7d 100644
--- a/crates/effects/src/sim.rs
+++ b/crates/effects/src/sim.rs
@@ -38,7 +38,7 @@ use particle_fx::{PW_RATE, mercury_phys, ps2_phys, pw_phys};
 pub use registry::{specs, sprite_plan};
 pub use sprites::{Acc, Post, Shape, Sprite, SpritePlan, Tint};
 pub(crate) use sprites::{combine, raster, splat};
-pub use weather::{Bubble, bubble_list, drizzle_drops};
+pub use weather::{Bubble, bubble_list, bubble_sample_bounds, drizzle_drops};
 
 #[cfg(test)]
 mod tests;
diff --git a/crates/effects/src/sim/tests.rs b/crates/effects/src/sim/tests.rs
index d5de4cb74..06ce973b2 100644
--- a/crates/effects/src/sim/tests.rs
+++ b/crates/effects/src/sim/tests.rs
@@ -112,6 +112,45 @@ fn bubbles_near_edges_show_the_layer() {
     assert_eq!(pale, [0, 0], "pale bubble pixels (liquid, metal)");
 }
 
+/// CC Bubbles on a 40 × 40 layer `img` at `scale`, in a buffer padded by 6 transparent pixels
+/// (a half-resolution preview's layout).
+fn padded_bubbles(img: Image, scale: f64, reflection: u32) -> Image {
+    let size = 40.0;
+    let s = crate::find("ec.sim.ccbubbles").unwrap();
+    let mut params = crate::Params { values: s.params.iter().map(|p| (p.id.to_string(), crate::default_value(p, [size; 2]))).collect() };
+    for (k, v) in [("bubbleAmount", num(200.0)), ("bubbleSize", num(3.0)), ("reflectionType", Value::Enum(reflection))] {
+        params.values.insert(k.into(), v);
+    }
+    let ctx = EffectCtx { params: &params, time: 0.3, layer_size: [size; 2], seed: 1, adjustment: false, env: EffectEnv::default() };
+    let mut b = Buf { img, offset: [0.0; 2], scale };
+    b.pad(6);
+    crate::apply(s, &ctx, b).img
+}
+
+/// #2024: the same when the buffer has transparent padding around the layer: samples past the
+/// layer's edges repeat its edge pixels, not the padding, and a clear hole inside the layer is
+/// still refracted as the pale colour.
+#[test]
+fn bubbles_near_padded_edges_show_the_layer() {
+    let blue = |side| Image::filled(side, side, [0.0, 0.0, 1.0, 1.0]);
+    let pale = |img: &Image| img.data.iter().filter(|p| (p[2] - p[0] - p[3]).abs() > 1e-4).count();
+    for (scale, side) in [(1.0, 40), (0.5, 20)] {
+        let counts = [0, 1].map(|reflection| {
+            let a = padded_bubbles(blue(side), scale, reflection);
+            assert!(a.data.iter().any(|p| p[3] > 0.5), "bubbles drawn");
+            pale(&a)
+        });
+        assert_eq!(counts, [0, 0], "pale bubble pixels at scale {scale} (liquid, metal)");
+    }
+    let mut holed = blue(40);
+    for y in 12..28 {
+        for x in 12..28 {
+            holed.set(x, y, [0.0; 4]);
+        }
+    }
+    assert!(pale(&padded_bubbles(holed, 1.0, 0)) > 0, "the hole refracts as the pale colour");
+}
+
 #[test]
 fn drizzle_ripples() {
     let a = run("ec.sim.ccdrizzle", &[], ramp(48, 48), 0.6);
diff --git a/crates/effects/src/sim/weather.rs b/crates/effects/src/sim/weather.rs
index b58b39b5e..347ab4939 100644
--- a/crates/effects/src/sim/weather.rs
+++ b/crates/effects/src/sim/weather.rs
@@ -1,6 +1,7 @@
 use super::common::{h, hs};
 use super::sprites::{Acc, Post, Shape, Sprite, SpritePlan, Tint, aa, raster};
 use super::{Buf, EffectCtx, Image, IntoParallelIterator, ParallelIterator, unpremul};
+use crate::util::layer_rect_at;
 
 // ------------------------------------------------------------------ CC Rainfall / CC Snowfall
 
@@ -160,11 +161,21 @@ pub fn bubble_list(ctx: &EffectCtx, b: &Buf) -> Vec<Bubble> {
         .collect()
 }
 
+/// CC Bubbles' refraction sample bounds in the pixels of a buffer with `offset` and `scale`: the
+/// layer rectangle's first and last pixel centres (x0, y0, x1, y1). Samples clamped to them repeat
+/// the layer's edge pixels instead of reaching transparent padding around it (#2024).
+pub fn bubble_sample_bounds(ctx: &EffectCtx, offset: [f64; 2], scale: f64) -> [f32; 4] {
+    let (lx, ly, lw, lh) = layer_rect_at(ctx, offset, scale);
+    let (x0, y0) = (lx + 0.5, ly + 0.5);
+    [x0 as f32, y0 as f32, (lx + lw - 0.5).max(x0) as f32, (ly + lh - 0.5).max(y0) as f32]
+}
+
 pub(super) fn bubbles(ctx: &EffectCtx, mut b: Buf) -> Buf {
     let pr = ctx.params;
     let metal = pr.e("reflectionType") == 1;
     let shading = pr.e("shadingType");
     let list = bubble_list(ctx, &b);
+    let [x0, y0, x1, y1] = bubble_sample_bounds(ctx, b.offset, b.scale);
     let src = b.img.clone();
     let mut out = Image::new(src.width, src.height);
     raster(
@@ -182,7 +193,8 @@ pub(super) fn bubbles(ctx: &EffectCtx, mut b: Buf) -> Buf {
             // Liquid refracts (inverted, magnified), metal reflects (wide-angle mirror).
             let k = if metal { 1.6 } else { -0.7 };
             let nz = (1.0 - d2).max(0.0).sqrt();
-            let p = src.sample_bilinear_clamped((q.sx + dx * q.r * k) as f64, (q.sy + dy * q.r * k) as f64);
+            let (sx, sy) = ((q.sx + dx * q.r * k).max(x0).min(x1), (q.sy + dy * q.r * k).max(y0).min(y1));
+            let p = src.sample_bilinear_clamped(sx as f64, sy as f64);
             let (c, sa) = unpremul(p);
             let mut c = if sa <= 0.0 { [0.6, 0.7, 0.8] } else { c };
             let mut a = cov;
diff --git a/crates/effects/tests/it/sim_golden.rs b/crates/effects/tests/it/sim_golden.rs
index 3932418ad..388790901 100644
--- a/crates/effects/tests/it/sim_golden.rs
+++ b/crates/effects/tests/it/sim_golden.rs
@@ -441,10 +441,10 @@ const GOLDEN: &[(&str, u64)] = &[
     ("ec.sim.ccbubbles/0/32bpc/t1.5", 0xd09565e124d8f5db),
     ("ec.sim.ccbubbles/0/32bpc/t0.8", 0x91242f8e1fd0ad84),
     ("ec.sim.ccbubbles/0/32bpc/t2.2", 0x1f9782131e62149d),
-    ("ec.sim.ccbubbles/0/8bpc/half/t0.5", 0x931b4ca707604220),
-    ("ec.sim.ccbubbles/0/8bpc/half/t1.5", 0x21c25d4555abebe9),
-    ("ec.sim.ccbubbles/0/8bpc/half/t0.8", 0x7e05972683359632),
-    ("ec.sim.ccbubbles/0/8bpc/half/t2.2", 0xadc4f7219dab4921),
+    ("ec.sim.ccbubbles/0/8bpc/half/t0.5", 0x020755e48bdf8f43),
+    ("ec.sim.ccbubbles/0/8bpc/half/t1.5", 0x4aac0f1332e6001e),
+    ("ec.sim.ccbubbles/0/8bpc/half/t0.8", 0xdc2ab5e04c4a95a2),
+    ("ec.sim.ccbubbles/0/8bpc/half/t2.2", 0x30f78adc5d1dd715),
     ("ec.sim.ccbubbles/1/8bpc/t0.5", 0x2f5415c679ff0980),
     ("ec.sim.ccbubbles/1/8bpc/t1.5", 0xfcfc354dcd22e6d0),
     ("ec.sim.ccbubbles/1/8bpc/t0.8", 0xdf90fd57c217019c),
diff --git a/crates/gpu/src/fx_sim.rs b/crates/gpu/src/fx_sim.rs
index a2d2c24dd..944ca6c07 100644
--- a/crates/gpu/src/fx_sim.rs
+++ b/crates/gpu/src/fx_sim.rs
@@ -253,6 +253,7 @@ fn bubbles(e: &mut Enc, ctx: &EffectCtx, b: GBuf, geo: &effectcraft_effects::Buf
     }
     let mut p = Params::default();
     p.u[1] = [0, (ctx.params.e("reflectionType") == 1) as u32, ctx.params.e("shadingType"), 0];
+    p.f[0] = effectcraft_effects::bubble_sample_bounds(ctx, b.offset, b.scale);
     let img = raster(e, items, 1, false, &b.img, None, p, w, h)?;
     Some(GBuf { img, ..b })
 }
diff --git a/crates/gpu/src/shaders/fx_sim.wgsl b/crates/gpu/src/shaders/fx_sim.wgsl
index 8ef3035fe..0c6023f32 100644
--- a/crates/gpu/src/shaders/fx_sim.wgsl
+++ b/crates/gpu/src/shaders/fx_sim.wgsl
@@ -165,7 +165,8 @@ fn fxm_sprite(at: u32, x: f32, y: f32) -> FxmShade {
     return FxmShade(true, vec4<f32>(rgb * a, a));
 }
 
-// CC Bubbles' bubble (sim::bubbles). u[1].y = metal, u[1].z = shading type.
+// CC Bubbles' bubble (sim::bubbles). u[1].y = metal, u[1].z = shading type, f[0] = the layer
+// rectangle's first and last pixel centres (x0, y0, x1, y1), which refraction samples stay within.
 fn fxm_bubble(at: u32, x: f32, y: f32) -> FxmShade {
     let qx = data[at + 1u];
     let qy = data[at + 2u];
@@ -180,7 +181,9 @@ fn fxm_bubble(at: u32, x: f32, y: f32) -> FxmShade {
     }
     let k = select(-0.7, 1.6, P.u[1].y != 0u);
     let nz = sqrt(max(1.0 - d2, 0.0));
-    let s = fxm_unpremul(sample_bilinear_clamped(src, data[at + 4u] + dx * qr * k, data[at + 5u] + dy * qr * k));
+    let sx = min(max(data[at + 4u] + dx * qr * k, P.f[0].x), P.f[0].z);
+    let sy = min(max(data[at + 5u] + dy * qr * k, P.f[0].y), P.f[0].w);
+    let s = fxm_unpremul(sample_bilinear_clamped(src, sx, sy));
     var c = s.xyz;
     if (s.w <= 0.0) {
         c = vec3<f32>(0.6, 0.7, 0.8);
diff --git a/crates/gpu/src/tests/fx_sim.rs b/crates/gpu/src/tests/fx_sim.rs
index dc2510bb3..4f54e07b6 100644
--- a/crates/gpu/src/tests/fx_sim.rs
+++ b/crates/gpu/src/tests/fx_sim.rs
@@ -105,6 +105,34 @@ fn bubbles_drizzle_mercury() {
     case("ec.sim.ccmrmercury", &[("birthRate", n(3.0)), ("blobInfluence", n(60.0)), ("shading/metal", n(80.0)), ("gravity", n(2.0))], 1.5, 0.0);
 }
 
+/// CC Bubbles on a buffer with transparent padding around the layer: both sides clamp the
+/// refraction samples to the layer rectangle, not to the buffer (#2024).
+#[test]
+fn bubbles_on_padded_buffers() {
+    let Some(g) = gpu() else { return };
+    let spec = effectcraft_effects::find("ec.sim.ccbubbles").unwrap();
+    let size = [70.0, 44.0];
+    for reflection in [0, 1] {
+        let mut params =
+            effectcraft_effects::Params { values: spec.params.iter().map(|ps| (ps.id.to_string(), effectcraft_effects::default_value(ps, size))).collect() };
+        for (k, v) in [("bubbleAmount", n(80.0)), ("bubbleSize", n(4.0)), ("reflectionType", e(reflection))] {
+            params.values.insert(k.to_string(), v);
+        }
+        for scale in [1.0, 0.5] {
+            let img = pattern(7, (size[0] * scale) as u32, (size[1] * scale) as u32);
+            let mut buf = effectcraft_effects::Buf { img, offset: [0.0, 0.0], scale };
+            buf.pad(6);
+            let ctx = || effectcraft_effects::EffectCtx { params: &params, time: 0.5, layer_size: size, seed: 11, adjustment: false, env: Default::default() };
+            let cpu = (spec.render)(&ctx(), buf.clone());
+            let out =
+                effectcraft_render::Accelerator::effects(g, &[effectcraft_render::FxStep { spec, ctx: ctx() }], &buf, None).expect("the GPU runs the effect");
+            assert_eq!((out.offset, out.scale), (cpu.offset, cpu.scale), "geometry");
+            let d = diff(&cpu.img, &out.img, 1e-3);
+            assert!(d.over == 0, "reflection {reflection} scale {scale}: {} of {} pixels over 1e-3 (max {}); worst {:?}", d.over, d.total, d.max, d.worst);
+        }
+    }
+}
+
 #[test]
 fn hair_wave_world_foam() {
     case("ec.sim.cchair", &[("density", n(300.0)), ("length", n(10.0))], 0.0, 0.0);

From dcbb806139fc3ab2425bb77c52e4142741af52be Mon Sep 17 00:00:00 2001
From: Krueels <90205419+Krueels@users.noreply.github.com>
Date: Sun, 25 Oct 2026 19:44:05 -0300
Subject: [PATCH 03/13] #986: add Blender scene export for 3D Camera Tracker

---
 contributors/people.toml                      |   3 +
 crates/engine/src/cmd.rs                      |   1 +
 crates/engine/src/cmd/blender.rs              | 295 ++++++++++++++++++
 crates/engine/src/cmd/blender/validate.rs     |  71 +++++
 crates/engine/src/cmd/blender_scene.py        | 206 ++++++++++++
 crates/engine/src/cmd/camera_cmds.rs          |  14 +
 crates/engine/src/tests.rs                    |   1 +
 crates/engine/src/tests/blender.rs            | 261 ++++++++++++++++
 crates/engine/tests/blender_scene_oracle.py   |  61 ++++
 crates/ui-egui/src/i18n/ui.rs                 |   1 +
 crates/ui-egui/src/menus/frontend.rs          |   1 +
 .../ui-egui/src/panels/camera_tracker_ui.rs   |   7 +-
 crates/ui-egui/tests/it/ui_camera_tracker.rs  |  61 +++-
 docs/agents.md                                |   7 +-
 docs/blender-camera-export.md                 | 101 ++++++
 15 files changed, 1086 insertions(+), 5 deletions(-)
 create mode 100644 crates/engine/src/cmd/blender.rs
 create mode 100644 crates/engine/src/cmd/blender/validate.rs
 create mode 100644 crates/engine/src/cmd/blender_scene.py
 create mode 100644 crates/engine/src/tests/blender.rs
 create mode 100644 crates/engine/tests/blender_scene_oracle.py
 create mode 100644 docs/blender-camera-export.md

diff --git a/contributors/people.toml b/contributors/people.toml
index 8654c7a10..df9d7fd80 100644
--- a/contributors/people.toml
+++ b/contributors/people.toml
@@ -17,6 +17,9 @@
 # To remove your names, delete your entry (or set fields empty) in a PR. The next
 # contributors.py run, and the next build, drop them.
 
+[people.Krueels]
+sync_github_name = true
+
 [people.echelon]
 real_name = "Brandon Thomas"
 display_name = "Brandon Thomas"
diff --git a/crates/engine/src/cmd.rs b/crates/engine/src/cmd.rs
index cba6df6ef..bd089b52b 100644
--- a/crates/engine/src/cmd.rs
+++ b/crates/engine/src/cmd.rs
@@ -10,6 +10,7 @@ mod animation;
 pub(crate) mod app_more;
 mod autotrace;
 mod batch;
+mod blender;
 mod camera_cmds;
 mod comp;
 pub(crate) mod comp_more;
diff --git a/crates/engine/src/cmd/blender.rs b/crates/engine/src/cmd/blender.rs
new file mode 100644
index 000000000..e6c678101
--- /dev/null
+++ b/crates/engine/src/cmd/blender.rs
@@ -0,0 +1,295 @@
+//! Camera-solve interchange through Blender's public Python API. The generated script is
+//! original MIT OR Apache-2.0 code; no Blender implementation is read or embedded.
+
+use std::path::Path;
+
+use effectcraft_effects::camera_tracker as ct;
+use effectcraft_project::{Footage, FootageKind, ItemId, ItemKind, Layer, LayerId, LayerSource, Uid};
+use effectcraft_render::EvalCtx;
+use effectcraft_time::Tick;
+use effectcraft_track::camtrack::{CameraSolve, linalg};
+use serde_json::{Value, json};
+
+mod validate;
+
+use super::{b_p, bad, f_p, str_p};
+use crate::{EngineError, Result, Session};
+
+const CMD: &str = "camera.exportBlender";
+const MAX_FRAMES: usize = 100_000;
+const MAX_POINTS: usize = 100_000;
+const MAX_JSON: usize = 64 * 1024 * 1024;
+const MAX_FRAME: i64 = 1_048_574;
+
+fn number(p: &Value, key: &str, default: f64, min: f64, max: f64) -> Result<f64> {
+    let v = match p.get(key) {
+        None => default,
+        Some(_) => f_p(p, key).ok_or_else(|| bad(CMD, format!("{key}: expected a number")))?,
+    };
+    if !v.is_finite() || !(min..=max).contains(&v) {
+        return Err(bad(CMD, format!("{key}: expected {min}..{max}")));
+    }
+    Ok(v)
+}
+
+fn finite(values: impl IntoIterator<Item = f64>) -> Result<()> {
+    if values.into_iter().any(|v| !v.is_finite() || v.abs() > 1e12) {
+        return Err(bad(CMD, "invalid or excessive numeric camera/scene data; re-analyze the tracker"));
+    }
+    Ok(())
+}
+
+/// Right-handed EffectCraft world (right, down, forward) → Blender (right, forward, up).
+fn position(p: [f64; 3], scale: f64) -> [f64; 3] {
+    [p[0] * scale, p[2] * scale, -p[1] * scale]
+}
+
+fn media_path(s: &Session, path: &str) -> Result<String> {
+    if path.is_empty() || path.contains('\0') {
+        return Err(bad(CMD, "the source footage has no valid file path; relink it before exporting"));
+    }
+    let path = Path::new(path);
+    if path.is_absolute() || cfg!(target_arch = "wasm32") {
+        return Ok(path.to_string_lossy().into_owned());
+    }
+    let cwd = std::env::current_dir().map_err(|e| bad(CMD, format!("cannot resolve footage path: {e}")))?;
+    let base = s.path.as_deref().and_then(|p| Path::new(p).parent()).map(|p| cwd.join(p)).unwrap_or(cwd);
+    Ok(base.join(path).to_string_lossy().into_owned())
+}
+
+pub(super) fn export(s: &mut Session, p: &Value, cid: ItemId, lid: LayerId, uid: Uid) -> Result<Value> {
+    if s.running_for_script() && !s.prefs.scripting.allow_scripts_write_files {
+        return Err(bad(CMD, "scripts can't export files unless Settings ▸ Scripting & Expressions ▸ Allow Scripts to Write Files and Access Network is on"));
+    }
+    let options = Options::parse(p)?;
+    let Options { path, sensor, units, start, include_points } = options;
+    if s.camera_target().is_some_and(|(c, l, u)| (c, l, u) == (cid, lid, uid)) && s.is_camera_analyzing() || s.camera_pending.contains(&(cid, lid, uid)) {
+        return Err(bad(CMD, "wait for this tracker's analysis to finish before exporting"));
+    }
+    let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
+    let layer = comp.layer(lid).ok_or_else(|| bad(CMD, "tracked layer missing"))?;
+    let g = layer.props.find_group(uid).ok_or_else(|| bad(CMD, "tracker missing"))?;
+    for name in [ct::SOLVE, ct::TRACKS] {
+        if g.prop(name).is_some_and(|p| matches!(&p.value, effectcraft_keyframe::Value::Str(v) if v.len() > MAX_JSON)) {
+            return Err(bad(CMD, "tracking data exceeds the 64 MiB export limit"));
+        }
+    }
+    let params = crate::camera_track::static_params(g);
+    let solve = ct::solve(&params).ok_or_else(|| bad(CMD, "the camera is not solved yet; analyze the tracker first"))?;
+    let (lo, end) = validate::timing(comp, layer, &solve, start)?;
+    let Source { footage, path: source_path, fps: source_fps, count: source_count } = source(s, layer, &solve, path)?;
+    validate::geometry(&solve, sensor)?;
+    let camera = params
+        .get(ct::CAMERA)
+        .map(|v| v.as_f64())
+        .filter(|v| v.is_finite() && *v > 0.0 && *v <= u64::MAX as f64)
+        .and_then(|id| comp.layer(LayerId(id as u64)))
+        .filter(|l| l.is_camera());
+    let warnings = scene_warnings(camera, &solve, footage);
+    let ctx = EvalCtx { expr: s.expr.as_deref(), ..EvalCtx::new(&s.project, cid, comp, lo) };
+    let (frames, world) = bake_frames(&ctx, layer, &solve, camera, &options, footage, source_count)?;
+    let mut points = Vec::new();
+    for point in &solve.points {
+        finite(point.pos.into_iter().chain([point.error as f64]))?;
+        if point.first > point.last || point.last as usize >= solve.frames.len() {
+            return Err(bad(CMD, "invalid solved point frame range; re-analyze the tracker"));
+        }
+        let location = position(world.apply(point.pos), units);
+        finite(location)?;
+        if include_points {
+            points.push(json!({"id": point.id, "location": location, "error": point.error,
+                "first": start.saturating_add(point.first as i64), "last": start.saturating_add(point.last as i64)}));
+        }
+    }
+    let tracks = ct::tracks(&params);
+    if tracks.as_ref().is_some_and(|t| t.tracks.len() > MAX_POINTS || t.tracks.iter().any(|t| t.pts.len() > MAX_FRAMES)) {
+        return Err(bad(CMD, "2D tracks exceed export limits"));
+    }
+    let markers: Vec<Value> = comp
+        .markers
+        .iter()
+        .filter_map(|m| {
+            let frame = start.saturating_add(comp.frame_rate.frame_at(m.time).saturating_sub(comp.frame_rate.frame_at(lo)));
+            if (start..=end).contains(&frame) { Some(json!({"name": m.comment, "frame": frame})) } else { None }
+        })
+        .collect();
+    let payload = json!({"version": 1, "name": format!("{} — {}", s.project.item(cid).map(|i| i.name.as_str()).unwrap_or("Shot"), layer.name),
+        "resolution": solve.size, "fpsNumerator": comp.frame_rate.num, "fpsDenominator": comp.frame_rate.den,
+        "startFrame": start, "endFrame": end, "sensorWidth": sensor, "unitScale": units,
+        "media": {"path": source_path, "kind": if footage.kind == FootageKind::Still {"FILE"} else {"MOVIE"},
+            "fps": source_fps, "nativeRate": footage.native_rate, "pixelAspect": footage.pixel_aspect, "timecode": footage.start_timecode,
+            "frameCount": source_count, "loopCount": footage.loop_count},
+        "frames": frames, "points": points, "markers": markers, "ground": solve.ground.is_some(),
+        "groundSize": world.s * units, "shutter": comp.shutter_angle / 360.0, "shutterPhase": comp.shutter_phase,
+        "solve": solve, "tracks": if include_points { tracks.as_deref() } else { None },
+        "warnings": warnings});
+    let data = serde_json::to_string(&payload).map_err(|e| bad(CMD, format!("cannot serialize scene: {e}")))?;
+    if data.len() > MAX_JSON {
+        return Err(bad(CMD, "scene exceeds the 64 MiB script limit; disable includePoints or split the shot"));
+    }
+    let quoted = serde_json::to_string(&data).map_err(|e| bad(CMD, format!("cannot encode scene: {e}")))?;
+    let script = include_str!("blender_scene.py").replace("__EFFECTCRAFT_DATA__", &quoted);
+    s.services.write_file(path, script.as_bytes()).map_err(|e| bad(CMD, format!("cannot write {path}: {e}")))?;
+    Ok(json!({"path": path, "bytes": script.len(), "frames": frames.len(), "points": points.len(), "warnings": warnings}))
+}
+
+struct Options<'a> {
+    path: &'a str,
+    sensor: f64,
+    units: f64,
+    start: i64,
+    include_points: bool,
+}
+
+impl<'a> Options<'a> {
+    fn parse(p: &'a Value) -> Result<Self> {
+        let path = str_p(p, "path").filter(|p| !p.is_empty() && !p.contains('\0')).ok_or_else(|| bad(CMD, "missing `path` (.py)"))?;
+        if !Path::new(path).extension().is_some_and(|e| e.eq_ignore_ascii_case("py")) {
+            return Err(bad(CMD, "the export path must end in .py"));
+        }
+        let sensor = number(p, "sensorWidth", 36.0, 1.0, 1000.0)?;
+        let units = number(p, "unitScale", 0.01, 0.000_001, 1000.0)?;
+        let start = match p.get("startFrame") {
+            None => 1,
+            Some(v) => v.as_i64().filter(|n| (1..=MAX_FRAME).contains(n)).ok_or_else(|| bad(CMD, "startFrame: expected a positive Blender frame number"))?,
+        };
+        let include_points = match p.get("includePoints") {
+            Some(v) if !v.is_boolean() => return Err(bad(CMD, "includePoints: expected a boolean")),
+            _ => b_p(p, "includePoints").unwrap_or(true),
+        };
+        Ok(Self { path, sensor, units, start, include_points })
+    }
+}
+
+struct Source<'a> {
+    footage: &'a Footage,
+    path: String,
+    fps: f64,
+    count: i64,
+}
+
+fn source<'a>(s: &'a Session, layer: &Layer, solve: &CameraSolve, path: &str) -> Result<Source<'a>> {
+    let footage = match layer.source {
+        LayerSource::Footage { item } => s.project.item(item).and_then(|i| match &i.kind {
+            ItemKind::Footage(f) => Some(f),
+            _ => None,
+        }),
+        _ => None,
+    }
+    .filter(|f| f.has_video && matches!(f.kind, FootageKind::Video | FootageKind::Still));
+    let footage = footage
+        .ok_or_else(|| bad(CMD, "Blender background export needs a video or still-footage layer; render precomps/sequences to a video and track that video"))?;
+    let source_path = media_path(s, &footage.path)?;
+    if Path::new(path) == Path::new(&source_path) {
+        return Err(bad(CMD, "the export path must differ from the source footage"));
+    }
+    if footage.width as f64 != solve.size[0] || footage.height as f64 != solve.size[1] {
+        return Err(bad(CMD, "the analysis image differs from the original footage dimensions; render the tracker's input to a video and track that video"));
+    }
+    let source_fps = footage.frame_rate.as_f64();
+    if footage.frame_rate.num <= 0 || footage.frame_rate.den <= 0 || !source_fps.is_finite() || source_fps <= 0.0 {
+        return Err(bad(CMD, "invalid source footage frame rate"));
+    }
+    // Same frame selection as the media pool: interpreted FPS, rounded per-loop frame count,
+    // clamp to the total loop range, then wrap. Native FPS does not change the frame index.
+    let divisor = (effectcraft_time::TICKS_PER_SECOND as i128).saturating_mul(footage.frame_rate.den as i128);
+    let source_count = (footage.duration.0 as i128).saturating_mul(footage.frame_rate.num as i128).saturating_add(divisor / 2) / divisor;
+    let source_count = if footage.kind == FootageKind::Still { 1 } else { source_count };
+    if !(1..=MAX_FRAME as i128).contains(&source_count) {
+        return Err(bad(CMD, "invalid footage duration or footage exceeds Blender's frame range; trim/render the source video first"));
+    }
+    let source_count = source_count as i64;
+    Ok(Source { footage, path: source_path, fps: source_fps, count: source_count })
+}
+
+fn scene_warnings(camera: Option<&Layer>, solve: &CameraSolve, footage: &Footage) -> Vec<String> {
+    let mut warnings = vec![
+        "Sensor width is assumed (36 mm by default); monocular tracking cannot recover physical sensor size or absolute scene scale.".to_string(),
+        "The original footage is referenced, not embedded or rendered: masks and effects before the tracker are not baked. Relink the video if moving this script.".to_string(),
+    ];
+    if camera.is_none() {
+        warnings
+            .push("No linked tracker camera: focus uses the default scene depth, DOF is off; optical focus cannot be recovered from feature tracks.".into());
+    } else {
+        warnings.push("Focus/iris settings are sampled from the linked camera; pose and lens come from the tracker solve. Blender's physical DOF is an approximation of EffectCraft's blur model.".into());
+    }
+    if solve.distortion.is_some_and(|d| !d.is_none()) {
+        warnings.push("Radial distortion is preserved as metadata (Brown k1/k2, half-diagonal normalization), not applied to Blender's pinhole camera. Use an undistorted plate for exact alignment.".into());
+    }
+    if (footage.pixel_aspect - 1.0).abs() > 1e-6 {
+        warnings.push("The tracker solves square pixels: export uses square pixels; original footage pixel aspect is retained in metadata.".into());
+    }
+    warnings
+}
+
+/// Bake the solved camera and the linked camera's optical settings at exact composition ticks.
+fn bake_frames(
+    ctx0: &EvalCtx<'_>,
+    layer: &Layer,
+    solve: &CameraSolve,
+    camera: Option<&Layer>,
+    options: &Options<'_>,
+    footage: &Footage,
+    source_count: i64,
+) -> Result<(Vec<Value>, linalg::Similarity)> {
+    let comp = ctx0.comp;
+    let lo = ctx0.time;
+    let fd = comp.frame_duration();
+    let sensor = options.sensor;
+    let units = options.units;
+    let start = options.start;
+    let first = solve.frames.first().ok_or_else(|| bad(CMD, "the camera solve is empty"))?;
+    let m = ctx0.world_matrix(layer).0;
+    let layer_scale = m[0][0].hypot(m[1][0]);
+    finite([layer_scale])?;
+    if layer_scale <= 1e-9 {
+        return Err(bad(CMD, "the tracked layer has zero scale"));
+    }
+    let world = solve.world([comp.width as f64, comp.height as f64], first.focal * layer_scale);
+    finite([world.s * units])?;
+    let mut frames = Vec::with_capacity(solve.frames.len());
+    for (i, frame) in solve.frames.iter().enumerate() {
+        let time = Tick(lo.0.saturating_add(fd.0.saturating_mul(i as i64)));
+        let ctx = ctx0.at(time);
+        let pose = linalg::mm(&world.r, &linalg::mt(&frame.r()));
+        let right = position(linalg::mv(&pose, [1.0, 0.0, 0.0]), 1.0);
+        let up = position(linalg::mv(&pose, [0.0, -1.0, 0.0]), 1.0);
+        let back = position(linalg::mv(&pose, [0.0, 0.0, -1.0]), 1.0);
+        let location = position(world.apply(frame.center), units);
+        let lens = frame.focal * sensor / solve.size[0];
+        let opts = camera.and_then(|l| l.props.sub("cameraOptions").map(|g| (l, g)));
+        let value = |key: &str, fallback: f64| opts.map(|(l, g)| ctx.f(l, g, key, fallback)).unwrap_or(fallback);
+        let focus = value("focusDistance", world.s) * units;
+        let aperture = value("aperture", 0.0);
+        let zoom = value("zoom", frame.focal * layer_scale);
+        // Match Camera Settings' f-stop conversion: focal_for_zoom uses a 36 mm film width,
+        // and the aperture UI is mm scaled by comp_width / 1920 (not a world-space diameter).
+        let aperture_mm = aperture * 1920.0 / comp.width as f64;
+        let fstop = if aperture_mm > 0.0 { (zoom * 36.0 / comp.width as f64) / aperture_mm } else { 2.8 };
+        let rotation = value("irisRotation", 0.0).to_radians();
+        let ratio = value("irisAspectRatio", 1.0);
+        let shape = opts.map(|(l, g)| ctx.e(l, g, "irisShape")).unwrap_or(0);
+        let blades = match shape {
+            0 => 4,
+            1..=8 => shape.saturating_add(2),
+            _ => return Err(bad(CMD, "invalid iris shape")),
+        };
+        let dof = opts.is_some_and(|(l, g)| ctx.b(l, g, "dof")) && aperture > 0.0 && value("blurLevel", 100.0) > 0.0;
+        let source_time = ctx.source_time(layer);
+        let source_frame = if footage.kind == FootageKind::Still {
+            0
+        } else {
+            footage.frame_rate.frame_at(source_time).clamp(0, source_count.saturating_mul(footage.loop_count.max(1) as i64).saturating_sub(1)) % source_count
+        };
+        finite(location.into_iter().chain([focus, aperture, zoom, fstop, rotation, ratio, value("blurLevel", 100.0), value("irisRoundness", 0.0)]))?;
+        if focus <= 0.0 || !(0.01..=100.0).contains(&ratio) || !(0.01..=1e6).contains(&fstop) {
+            return Err(bad(CMD, "focus, f-stop or iris aspect is outside Blender's supported range"));
+        }
+        frames.push(json!({"frame": start + i as i64, "timeTicks": time.0, "sourceFrame": source_frame,
+            "location": location, "rotation": [right, up, back], "lens": lens, "focus": focus, "dof": dof,
+            "fstop": fstop, "blades": blades, "irisRotation": rotation, "irisRatio": ratio,
+            "sourceAperture": aperture, "sourceZoom": zoom,
+            "blurLevel": value("blurLevel", 100.0), "irisRoundness": value("irisRoundness", 0.0)}));
+    }
+    Ok((frames, world))
+}
diff --git a/crates/engine/src/cmd/blender/validate.rs b/crates/engine/src/cmd/blender/validate.rs
new file mode 100644
index 000000000..a9454861f
--- /dev/null
+++ b/crates/engine/src/cmd/blender/validate.rs
@@ -0,0 +1,71 @@
+//! Validate solved geometry and its correspondence to the current layer timing.
+
+use effectcraft_project::{Comp, Layer};
+use effectcraft_time::Tick;
+use effectcraft_track::camtrack::{CameraSolve, linalg};
+
+use super::{CMD, MAX_FRAME, MAX_FRAMES, MAX_POINTS, bad, finite};
+use crate::Result;
+
+pub(super) fn timing(comp: &Comp, layer: &Layer, solve: &CameraSolve, start: i64) -> Result<(Tick, i64)> {
+    if solve.frames.len() > MAX_FRAMES || solve.points.len() > MAX_POINTS {
+        return Err(bad(CMD, "export is limited to 100,000 frames and 100,000 points; split the shot"));
+    }
+    if solve.size.iter().any(|v| !v.is_finite() || *v < 4.0 || *v > 65_536.0 || v.fract() != 0.0) {
+        return Err(bad(CMD, "invalid tracking resolution (expected 4..65536 whole pixels)"));
+    }
+    let fps = comp.frame_rate.as_f64();
+    if comp.frame_rate.num <= 0 || comp.frame_rate.den <= 0 || !fps.is_finite() || !(1.0..=1000.0).contains(&fps) {
+        return Err(bad(CMD, "invalid composition frame rate (expected 1..1000 fps)"));
+    }
+    let end = start
+        .checked_add(solve.frames.len() as i64)
+        .and_then(|n| n.checked_sub(1))
+        .filter(|n| *n <= MAX_FRAME)
+        .ok_or_else(|| bad(CMD, "the baked animation exceeds Blender's frame range"))?;
+    finite([solve.start, solve.frame_duration, solve.average_error, layer.stretch, comp.shutter_angle, comp.shutter_phase])?;
+    if layer.stretch == 0.0 || comp.width == 0 || comp.height == 0 {
+        return Err(bad(CMD, "invalid composition dimensions or zero layer stretch"));
+    }
+    let lo = comp.frame_rate.snap_nearest(layer.in_point.max(Tick::ZERO));
+    let hi = layer.out_point.min(comp.duration);
+    let fd = comp.frame_duration();
+    if fd.0 <= 0 || lo >= hi {
+        return Err(bad(CMD, "the tracked layer has no active frames"));
+    }
+    let expected = ((hi.0 as i128 - lo.0 as i128 + fd.0 as i128 - 1) / fd.0 as i128) as u128;
+    if expected != solve.frames.len() as u128 {
+        return Err(bad(CMD, "the solve no longer matches the layer's frame range; re-analyze the tracker"));
+    }
+    let dt = (layer.layer_time(lo + fd) - layer.layer_time(lo)).seconds();
+    if (solve.start - layer.layer_time(lo).seconds()).abs() > 1e-6 || solve.frames.len() > 1 && (solve.frame_duration - dt).abs() > 1e-6 {
+        return Err(bad(CMD, "the solve no longer matches the layer's timing; re-analyze the tracker"));
+    }
+    Ok((lo, end))
+}
+
+pub(super) fn geometry(solve: &CameraSolve, sensor: f64) -> Result<()> {
+    for frame in &solve.frames {
+        finite(frame.rot.into_iter().chain(frame.center).chain([frame.focal]))?;
+        if !frame.solved || frame.focal <= 0.0 {
+            return Err(bad(CMD, "the solve contains unsolved frames or invalid focal lengths; re-analyze the tracker"));
+        }
+        let mm = sensor * frame.focal / solve.size[0];
+        if !(1.0..=5000.0).contains(&mm) {
+            return Err(bad(CMD, "lens outside Blender's 1..5000 mm range; choose another sensorWidth"));
+        }
+    }
+    if let Some(ground) = &solve.ground {
+        finite(ground.origin.into_iter().chain(ground.normal).chain(ground.x_axis))?;
+        if (linalg::norm(ground.normal) - 1.0).abs() > 1e-4
+            || (linalg::norm(ground.x_axis) - 1.0).abs() > 1e-4
+            || linalg::dot(ground.normal, ground.x_axis).abs() > 1e-4
+        {
+            return Err(bad(CMD, "invalid ground-plane basis; set the ground plane again"));
+        }
+    }
+    if let Some(d) = &solve.distortion {
+        finite([d.k1, d.k2, d.radius])?;
+    }
+    Ok(())
+}
diff --git a/crates/engine/src/cmd/blender_scene.py b/crates/engine/src/cmd/blender_scene.py
new file mode 100644
index 000000000..7240cb1ca
--- /dev/null
+++ b/crates/engine/src/cmd/blender_scene.py
@@ -0,0 +1,206 @@
+# EffectCraft camera tracker → Blender, original code under MIT OR Apache-2.0.
+# Blender scene export contributor: Krueels — https://github.com/Krueels
+# Run in Blender's Scripting workspace (Open, Run Script), or:
+# blender --background --python "Tracked Scene.py"
+# Creates a NEW scene; existing scenes and objects are preserved. Save the .blend yourself.
+# Public API references: https://docs.blender.org/api/4.5/bpy.types.Camera.html
+# https://docs.blender.org/api/4.5/bpy.types.ImageUser.html
+import json
+import math
+import os
+
+import bpy
+from mathutils import Matrix
+
+DATA = json.loads(__EFFECTCRAFT_DATA__)
+
+
+def _curves(owner):
+    """Blender 4.0–4.3 legacy actions and 4.4+/5.x layered actions."""
+    anim = owner.animation_data
+    if anim is None or anim.action is None:
+        return
+    action = anim.action
+    if getattr(action, "is_action_layered", False):
+        for layer in action.layers:
+            for strip in layer.strips:
+                if strip.type == 'KEYFRAME':
+                    bag = strip.channelbag(anim.action_slot)
+                    if bag is not None:
+                        yield from bag.fcurves
+    else:
+        yield from action.fcurves
+
+
+def _interpolation(owner):
+    for curve in _curves(owner):
+        # Footage indices and discrete switches must never interpolate between frames.
+        stepped = ("frame_offset" in curve.data_path or "use_dof" in curve.data_path
+                   or "aperture_blades" in curve.data_path)
+        for key in curve.keyframe_points:
+            key.interpolation = 'CONSTANT' if stepped else 'LINEAR'
+
+
+def _media_path():
+    original = DATA["media"]["path"]
+    candidates = [original]
+    # When sharing, place the video alongside the script or the .blend and run again.
+    script_path = globals().get("__file__", "")
+    if script_path:
+        candidates.append(os.path.join(os.path.dirname(os.path.abspath(script_path)),
+                                       os.path.basename(original)))
+    if bpy.data.filepath:
+        candidates.append(os.path.join(os.path.dirname(bpy.data.filepath),
+                                       os.path.basename(original)))
+    return next((p for p in candidates if os.path.isfile(p)), None)
+
+
+def import_scene():
+    if bpy.app.version < (4, 0, 0):
+        raise RuntimeError("EffectCraft scene import requires Blender 4.0 or newer")
+    scene = bpy.data.scenes.new(DATA["name"])
+    scene.frame_start = DATA["startFrame"]
+    scene.frame_end = DATA["endFrame"]
+    fps = DATA["fpsNumerator"] / DATA["fpsDenominator"]
+    scene.render.fps = max(1, round(fps))
+    scene.render.fps_base = scene.render.fps / fps
+    scene.render.resolution_x, scene.render.resolution_y = map(int, DATA["resolution"])
+    scene.render.resolution_percentage = 100
+    # The tracker assumes square pixels, regardless of the source's interpretation metadata.
+    scene.render.pixel_aspect_x = scene.render.pixel_aspect_y = 1.0
+    scene.render.film_transparent = True
+    scene.render.motion_blur_shutter = max(0.0, min(2.0, DATA["shutter"]))
+    scene.unit_settings.system = 'METRIC'
+    scene.unit_settings.scale_length = 1.0
+    scene["effectcraft_unit_scale"] = DATA["unitScale"]
+    scene["effectcraft_scale_is_arbitrary"] = True
+    scene["effectcraft_shutter_phase_degrees"] = DATA["shutterPhase"]
+
+    collection = bpy.data.collections.new("EffectCraft Tracking")
+    scene.collection.children.link(collection)
+    camera_data = bpy.data.cameras.new("3D Tracker Camera")
+    camera = bpy.data.objects.new("3D Tracker Camera", camera_data)
+    collection.objects.link(camera)
+    scene.camera = camera
+    camera.rotation_mode = 'QUATERNION'
+    camera_data.type = 'PERSP'
+    camera_data.sensor_fit = 'HORIZONTAL'
+    camera_data.sensor_width = DATA["sensorWidth"]
+    camera_data.sensor_height = (DATA["sensorWidth"] * DATA["resolution"][1]
+                                 / DATA["resolution"][0])
+    camera_data.show_background_images = True
+    camera_data.show_limits = True
+    extent = max([DATA["groundSize"], 1.0]
+                 + [math.dist(p["location"], f["location"])
+                    for p in DATA["points"][::max(1, len(DATA["points"]) // 100)]
+                    for f in DATA["frames"][::max(1, len(DATA["frames"]) // 10)]])
+    camera_data.clip_start = max(0.00001, min(0.1, extent / 10000.0))
+    camera_data.clip_end = max(1000.0, extent * 10.0)
+
+    previous = None
+    for sample in DATA["frames"]:
+        frame = sample["frame"]
+        camera.location = sample["location"]
+        # Exported right/up/back vectors are COLUMNS of Blender's local → world basis.
+        quaternion = Matrix(sample["rotation"]).transposed().to_quaternion()
+        if previous is not None and previous.dot(quaternion) < 0:
+            quaternion.negate()
+        camera.rotation_quaternion = quaternion
+        previous = quaternion.copy()
+        camera.keyframe_insert(data_path="location", frame=frame)
+        camera.keyframe_insert(data_path="rotation_quaternion", frame=frame)
+        camera_data.lens = sample["lens"]
+        camera_data.keyframe_insert(data_path="lens", frame=frame)
+        camera_data.dof.use_dof = sample["dof"]
+        camera_data.dof.focus_distance = sample["focus"]
+        camera_data.dof.aperture_fstop = sample["fstop"]
+        camera_data.dof.aperture_blades = sample["blades"]
+        camera_data.dof.aperture_rotation = (sample["irisRotation"] + math.pi) % math.tau - math.pi
+        camera_data.dof.aperture_ratio = sample["irisRatio"]
+        for prop in ("use_dof", "focus_distance", "aperture_fstop", "aperture_blades",
+                     "aperture_rotation", "aperture_ratio"):
+            camera_data.keyframe_insert(data_path="dof." + prop, frame=frame)
+
+    path = _media_path()
+    if path is not None:
+        try:
+            image = bpy.data.images.load(path, check_existing=False)
+            image.source = DATA["media"]["kind"]
+            background = camera_data.background_images.new()
+            background.source = 'IMAGE'
+            background.image = image
+            background.alpha = 1.0
+            background.display_depth = 'BACK'
+            background.frame_method = 'STRETCH'
+            user = background.image_user
+            user.use_auto_refresh = True
+            user.use_cyclic = False
+            user.frame_start = DATA["startFrame"]
+            user.frame_duration = max(1, min(1048574, image.frame_duration))
+            if image.source == 'MOVIE':
+                for sample in DATA["frames"]:
+                    # Blender uses 1-based image frames; sourceFrame is 0-based.
+                    user.frame_offset = sample["sourceFrame"] - (sample["frame"] - user.frame_start)
+                    camera_data.keyframe_insert(
+                        data_path="background_images[0].image_user.frame_offset",
+                        frame=sample["frame"])
+        except (RuntimeError, ValueError, OSError) as error:
+            DATA["warnings"].append("Blender could not load the background video: " + str(error))
+    else:
+        DATA["warnings"].append("Video not found: " + DATA["media"]["path"]
+                                + ". Place it beside this script or relink the camera background.")
+
+    if DATA["points"]:
+        mesh = bpy.data.meshes.new("Solved Track Points")
+        mesh.from_pydata([p["location"] for p in DATA["points"]], [], [])
+        mesh.update()
+        cloud = bpy.data.objects.new("Solved Track Points", mesh)
+        collection.objects.link(cloud)
+        cloud.show_in_front = True
+        cloud.hide_render = True
+        for name, kind, key in (("track_id", 'INT', "id"), ("reprojection_error", 'FLOAT', "error"),
+                                ("first_frame", 'INT', "first"), ("last_frame", 'INT', "last")):
+            attr = mesh.attributes.new(name=name, type=kind, domain='POINT')
+            for dest, point in zip(attr.data, DATA["points"]):
+                # Track IDs are u32 in EffectCraft; keep the full IDs in the JSON text too.
+                dest.value = point[key] if kind == 'FLOAT' else min(2147483647, point[key])
+
+    if DATA["ground"]:
+        size = DATA["groundSize"]
+        mesh = bpy.data.meshes.new("Solved Ground Plane")
+        mesh.from_pydata([(-size, -size, 0), (size, -size, 0),
+                          (size, size, 0), (-size, size, 0)], [], [(0, 1, 2, 3)])
+        mesh.update()
+        ground = bpy.data.objects.new("Solved Ground Plane", mesh)
+        collection.objects.link(ground)
+        ground.display_type = 'WIRE'
+        ground.hide_render = True
+    for marker in DATA["markers"]:
+        scene.timeline_markers.new(marker["name"], frame=marker["frame"])
+
+    _interpolation(camera)
+    _interpolation(camera_data)
+    metadata = bpy.data.texts.new("EffectCraft Tracking Metadata.json")
+    metadata.write(json.dumps(DATA, ensure_ascii=False, indent=2))
+    scene["effectcraft_metadata_text"] = metadata.name
+    camera_data["effectcraft_average_error_pixels"] = DATA["solve"]["averageError"]
+    camera_data["effectcraft_solve_method"] = DATA["solve"]["methodUsed"]
+    camera_data["effectcraft_focus_source"] = "See warnings in " + metadata.name
+    distortion = DATA["solve"].get("distortion")
+    if distortion:
+        for key in ("k1", "k2", "radius"):
+            camera_data["effectcraft_distortion_" + key] = distortion[key]
+    if bpy.context.window is not None:
+        bpy.context.window.scene = scene
+        for area in bpy.context.window.screen.areas:
+            if area.type == 'VIEW_3D':
+                area.spaces.active.region_3d.view_perspective = 'CAMERA'
+    scene.frame_set(scene.frame_start)
+    for warning in DATA["warnings"]:
+        print("EffectCraft: " + warning)
+    print("EffectCraft: imported", len(DATA["frames"]), "baked camera frames into", scene.name)
+    return scene
+
+
+if __name__ == "__main__":
+    EFFECTCRAFT_SCENE = import_scene()
diff --git a/crates/engine/src/cmd/camera_cmds.rs b/crates/engine/src/cmd/camera_cmds.rs
index 68cd14fb9..e717d51cc 100644
--- a/crates/engine/src/cmd/camera_cmds.rs
+++ b/crates/engine/src/cmd/camera_cmds.rs
@@ -42,11 +42,25 @@ pub fn specs() -> Vec<CommandSpec> {
             create_from_solve
         ),
         cmd!("camera.create", "Create Camera", [], None, "{layer?, effect?}", has_comp, |s, p| create_from_solve(s, &with_kind(p, "camera"))),
+        cmd!(
+            "camera.exportBlender",
+            "Export Scene to Blender...",
+            [],
+            None,
+            "{path: .py, comp?, layer?, effect?, sensorWidth?: mm (default 36), unitScale?: Blender units per comp pixel (default 0.01), startFrame?: positive integer (default 1), includePoints?: true}",
+            has_comp,
+            export_blender
+        ),
         cmd!("camera.setGroundPlane", "Set Ground Plane and Origin", [], None, "{points?: [id] (default: selected), layer?, effect?}", has_comp, set_ground),
         cmd!("camera.deletePoints", "Delete Selected Points", [], None, "{points?: [id] (default: selected), layer?, effect?, wait?}", has_comp, delete_points),
     ]
 }
 
+fn export_blender(s: &mut Session, p: &Value) -> Result<Value> {
+    let (cid, lid, uid) = ct_p(s, p, "camera.exportBlender")?;
+    super::blender::export(s, p, cid, lid, uid)
+}
+
 fn with_kind(p: &Value, kind: &str) -> Value {
     let mut q = p.clone();
     if !q.is_object() {
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 25d05b903..ac887f438 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -1,5 +1,6 @@
 mod anim_presets;
 mod anim_tools;
+mod blender;
 mod camera_track;
 mod codec_options;
 mod color_view;
diff --git a/crates/engine/src/tests/blender.rs b/crates/engine/src/tests/blender.rs
new file mode 100644
index 000000000..84e939055
--- /dev/null
+++ b/crates/engine/src/tests/blender.rs
@@ -0,0 +1,261 @@
+//! Synthetic camera interchange: projection, timing, DOF and hostile inputs. Optional public
+//! Blender-API oracle: EFFECTCRAFT_BLENDER=/path/to/blender cargo test -p effectcraft-engine tests::blender -- --nocapture.
+
+use effectcraft_effects::camera_tracker as ct;
+use effectcraft_keyframe::Value as KV;
+use effectcraft_project::{Footage, FootageKind, ItemKind, LayerId, LayerSource, build};
+use effectcraft_time::{FrameRate, Tick};
+use effectcraft_track::camtrack::{CameraSolve, Distortion, Ground, ShotType, SolveMethod, SolvedFrame, SolvedPoint};
+use serde_json::{Value, json};
+
+use crate::Session;
+
+fn path(name: &str) -> String {
+    let dir = std::env::temp_dir().join(format!("effectcraft-blender-tests-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    dir.join(name).to_string_lossy().into_owned()
+}
+
+fn fixture(ground: bool) -> (Session, LayerId, u64) {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Shot '\\ — câmera", "width": 640, "height": 360, "duration": 6})).unwrap();
+    let cid = s.active_comp_id().unwrap();
+    let rate = FrameRate::new(30000, 1001);
+    let lid = s
+        .edit("fixture", None, |p, _| {
+            p.comp_mut(cid).unwrap().frame_rate = rate;
+            let item = p.add_item(
+                "Plate",
+                Default::default(),
+                None,
+                ItemKind::Footage(Footage {
+                    path: std::env::var("EFFECTCRAFT_BLENDER_PLATE").unwrap_or_else(|_| path("plate '\\ — vídeo.mp4")),
+                    width: 640,
+                    height: 360,
+                    frame_rate: FrameRate::FPS_30,
+                    duration: Tick::from_seconds_f64(6.0),
+                    kind: FootageKind::Video,
+                    has_video: true,
+                    ..Default::default()
+                }),
+            );
+            let comp = p.comp(cid).unwrap().clone();
+            let mut layer = build::layer(p, &comp, "Tracked Video", LayerSource::Footage { item }, (640, 360), None);
+            layer.in_point = rate.tick_of(60);
+            layer.out_point = rate.tick_of(63);
+            layer.start_time = rate.tick_of(30);
+            layer.stretch = 200.0;
+            let id = layer.id;
+            p.comp_mut(cid).unwrap().layers.push(layer);
+            Ok(id)
+        })
+        .unwrap();
+    let uid = s.execute("effect.apply", json!({"effect": ct::ID, "layers": [lid.0]})).unwrap()["effects"][0].as_u64().unwrap();
+    let solve = CameraSolve {
+        version: 1,
+        size: [640.0, 360.0],
+        start: rate.tick_of(30).seconds() / 2.0,
+        frame_duration: rate.frame_duration().seconds() / 2.0,
+        shot: ShotType::VariableZoom,
+        method_used: SolveMethod::Typical,
+        average_error: 0.12,
+        frames: (0..3)
+            .map(|i| SolvedFrame {
+                rot: [0.02 * i as f64, -0.03 * i as f64, 0.01 * i as f64],
+                center: [0.1 * i as f64, -0.01 * i as f64, 0.02 * i as f64],
+                focal: 600.0 + i as f64 * 25.0,
+                solved: true,
+            })
+            .collect(),
+        points: vec![
+            SolvedPoint { id: 7, pos: [0.1, 0.2, 2.0], error: 0.13, first: 0, last: 2 },
+            SolvedPoint { id: 9, pos: [-0.3, -0.1, 1.2], error: 0.11, first: 0, last: 1 },
+        ],
+        ground: ground.then_some(Ground { origin: [0.1, 0.2, 2.0], normal: [0.0, -1.0, 0.0], x_axis: [1.0, 0.0, 0.0] }),
+        distortion: ground.then_some(Distortion { k1: 0.01, k2: -0.002, radius: 320.0_f64.hypot(180.0) }),
+    };
+    // Directly install a deterministic solve; no analysis or decoder is needed by these tests.
+    s.execute("prop.set", json!({"layer": lid.0, "path": "effects/#1/solve", "value": solve.to_json()})).unwrap();
+    s.camera_pending.clear();
+    s.execute("layer.select", json!({"layers": [lid.0]})).unwrap();
+    (s, lid, uid)
+}
+
+fn data(script: &str) -> Value {
+    let line = script.lines().find_map(|l| l.strip_prefix("DATA = json.loads(")).unwrap().strip_suffix(')').unwrap();
+    let encoded: String = serde_json::from_str(line).unwrap();
+    serde_json::from_str(&encoded).unwrap()
+}
+
+#[test]
+fn blender_export_bakes_projection_focus_and_retimed_background() {
+    let (mut s, lid, uid) = fixture(true);
+    let result = s.execute("camera.create", json!({"layer": lid.0, "effect": uid})).unwrap();
+    let camera = result["camera"].as_u64().unwrap();
+    s.execute("layer.cameraSettings", json!({"layer": camera, "focusDistance": 800.0, "dof": true, "fStop": 4.0, "lockToZoom": false})).unwrap();
+    for (frame, value) in [(60, 800.0), (62, 1000.0)] {
+        let time = FrameRate::new(30000, 1001).tick_of(frame).seconds();
+        s.execute("prop.addKey", json!({"layer": camera, "path": "cameraOptions/focusDistance", "time": time, "value": value})).unwrap();
+    }
+    let camera_layer = s.active_comp().unwrap().layer(LayerId(camera)).unwrap();
+    assert!(camera_layer.props.prop("cameraOptions/dof").unwrap().value.as_bool());
+    let output = path("oracle-scene.py");
+    let before = s.project.to_json();
+    let r = s.execute_checked("camera.exportBlender", json!({"layer": lid.0, "effect": uid, "path": output, "startFrame": 101})).unwrap();
+    assert_eq!(s.project.to_json(), before, "export must not edit the document");
+    assert_eq!(r["frames"], 3);
+    assert_eq!(r["points"], 2);
+    let script = std::fs::read_to_string(&output).unwrap();
+    let d = data(&script);
+    assert_eq!(d["resolution"], json!([640.0, 360.0]));
+    assert_eq!(d["fpsNumerator"], 30000);
+    assert_eq!(d["fpsDenominator"], 1001);
+    assert_eq!(d["frames"][0]["sourceFrame"], 15, "trim + 200% stretch, not scene frame 101");
+    assert_eq!(d["frames"][2]["sourceFrame"], 16);
+    assert_eq!(d["frames"][0]["focus"], 8.0);
+    assert_eq!(d["frames"][2]["focus"], 10.0);
+    assert_eq!(d["frames"][0]["dof"], true);
+    assert!((d["frames"][0]["fstop"].as_f64().unwrap() - 4.0).abs() < 1e-6);
+    assert_eq!(d["frames"][0]["lens"], 33.75);
+    assert_eq!(d["frames"][2]["lens"], 36.5625);
+    assert_eq!(d["ground"], true);
+    assert_eq!(d["solve"]["distortion"]["k1"], 0.01);
+    assert_eq!(d["points"][0]["location"][2], 0.0, "ground point lies on Blender XY plane");
+
+    // Execute the actual exported artifact in a separately installed Blender, when requested.
+    if let Ok(blender) = std::env::var("EFFECTCRAFT_BLENDER") {
+        let oracle = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/blender_scene_oracle.py");
+        let output = std::process::Command::new(blender)
+            .args(["--background", "--factory-startup", "--python-exit-code", "1", "--python"])
+            .arg(oracle)
+            .arg("--")
+            .arg(&output)
+            .output()
+            .unwrap();
+        assert!(output.status.success(), "Blender oracle failed:\n{}\n{}", String::from_utf8_lossy(&output.stdout), String::from_utf8_lossy(&output.stderr));
+        assert!(String::from_utf8_lossy(&output.stdout).contains("EFFECTCRAFT_BLENDER_ORACLE_OK"));
+    }
+}
+
+#[test]
+fn blender_export_bakes_reverse_time_remap_and_footage_loops() {
+    let (mut s, lid, _) = fixture(false);
+    let cid = s.active_comp_id().unwrap();
+    let rate = FrameRate::new(30000, 1001);
+    s.edit("retimed fixture", None, |p, _| {
+        let layer = p.comp(cid).unwrap().layer(lid).unwrap();
+        let item = layer.source.item().unwrap();
+        let keys = [(60, 8.0), (61, 6.0), (62, -1.0)]
+            .map(|(frame, time)| effectcraft_keyframe::Keyframe::new(layer.layer_time(rate.tick_of(frame)), KV::Scalar(time)));
+        let mut remap = build::Ids(&mut p.next_id).prop("timeRemap", "Time Remap", KV::Scalar(8.0));
+        remap.keys = keys.to_vec();
+        p.comp_mut(cid).unwrap().layer_mut(lid).unwrap().props.children.push(remap.into());
+        if let ItemKind::Footage(f) = &mut p.item_mut(item).unwrap().kind {
+            f.loop_count = 2;
+        }
+        Ok(())
+    })
+    .unwrap();
+    let output = path("remap.py");
+    s.execute_checked("camera.exportBlender", json!({"layer": lid.0, "path": output})).unwrap();
+    let d = data(&std::fs::read_to_string(output).unwrap());
+    let indices: Vec<i64> = d["frames"].as_array().unwrap().iter().map(|f| f["sourceFrame"].as_i64().unwrap()).collect();
+    assert_eq!(indices, vec![60, 0, 0], "reverse remap wraps the 6-second video and clamps negative source time, as the media pool does");
+}
+
+#[test]
+fn blender_export_defaults_and_script_escaping() {
+    let (mut s, lid, _) = fixture(false);
+    let output = path("escaped.py");
+    let r = s
+        .execute_checked("camera.exportBlender", json!({"layer": lid.0, "path": output, "includePoints": false, "sensorWidth": 24.0, "unitScale": 0.1}))
+        .unwrap();
+    assert_eq!(r["points"], 0);
+    let script = std::fs::read_to_string(&output).unwrap();
+    let d = data(&script);
+    assert!(d["name"].as_str().unwrap().contains("'\\ — câmera"));
+    assert_eq!(d["frames"][0]["lens"], 22.5);
+    assert_eq!(d["frames"][0]["dof"], false);
+    assert!(r["warnings"].as_array().unwrap().iter().any(|w| w.as_str().unwrap().contains("cannot be recovered")));
+    match std::process::Command::new("python3").args(["-c", "import ast,sys; ast.parse(open(sys.argv[1], encoding='utf-8').read())", &output]).status() {
+        Ok(status) => assert!(status.success(), "generated script must parse even with quoted/Unicode paths"),
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => eprintln!("Python AST oracle skipped: python3 is not installed"),
+        Err(e) => panic!("Python AST oracle failed: {e}"),
+    }
+}
+
+#[test]
+fn blender_export_rejects_invalid_arguments_and_write_failures() {
+    let (mut s, lid, _) = fixture(false);
+    for params in [
+        json!({"sensorWidth": 0}),
+        json!({"sensorWidth": "wide"}),
+        json!({"unitScale": -1}),
+        json!({"startFrame": -1}),
+        json!({"startFrame": 1.5}),
+        json!({"startFrame": 1048574}),
+        json!({"includePoints": "yes"}),
+        json!({"bogus": true}),
+        json!({"path": path("bad.blend")}),
+    ] {
+        let mut p = json!({"layer": lid.0, "path": path("invalid.py")});
+        p.as_object_mut().unwrap().extend(params.as_object().unwrap().clone());
+        assert!(s.execute_checked("camera.exportBlender", p.clone()).is_err(), "must reject {p}");
+    }
+    let blocker = path("blocker");
+    std::fs::write(&blocker, b"not a directory").unwrap();
+    let p = format!("{blocker}/scene.py");
+    assert!(s.execute_checked("camera.exportBlender", json!({"layer": lid.0, "path": p})).unwrap_err().to_string().contains("cannot write"));
+}
+
+#[test]
+fn blender_export_rejects_malformed_solves_without_panicking() {
+    for variant in ["empty", "unsolved", "zero-focal", "bad-ground", "huge-resolution", "mismatched-range"] {
+        let (mut s, lid, uid) = fixture(false);
+        let cid = s.active_comp_id().unwrap();
+        let mut solve = ct::solve(&crate::camera_track::static_params(s.active_comp().unwrap().layer(lid).unwrap().props.find_group(uid).unwrap()))
+            .unwrap()
+            .as_ref()
+            .clone();
+        match variant {
+            "empty" => solve.frames.clear(),
+            "unsolved" => solve.frames[0].solved = false,
+            "zero-focal" => solve.frames[0].focal = 0.0,
+            "bad-ground" => solve.ground = Some(Ground::default()),
+            "huge-resolution" => solve.size[0] = 1e10,
+            _ => {
+                solve.frames.pop();
+            }
+        }
+        s.edit("corrupt solve", None, |p, _| {
+            p.comp_mut(cid).unwrap().layer_mut(lid).unwrap().props.find_group_mut(uid).unwrap().prop_mut(ct::SOLVE).unwrap().value = KV::Str(solve.to_json());
+            Ok(())
+        })
+        .unwrap();
+        s.camera_pending.clear();
+        let result = s.execute_checked("camera.exportBlender", json!({"layer": lid.0, "path": path("corrupt.py")}));
+        assert!(result.is_err(), "must reject {variant}");
+    }
+}
+
+#[test]
+fn blender_export_respects_script_write_permission() {
+    let (mut s, lid, _) = fixture(false);
+    let output = path("script-permissions.py");
+    let params = json!({"layer": lid.0, "path": output});
+    for (from_script, allowed) in [(true, false), (true, true), (false, false), (false, true)] {
+        std::fs::write(&output, b"existing file").unwrap();
+        s.prefs.scripting.allow_scripts_write_files = allowed;
+        let result =
+            if from_script { s.execute_for_script("camera.exportBlender", params.clone()) } else { s.execute_checked("camera.exportBlender", params.clone()) };
+        assert!(!s.running_for_script(), "script origin must be restored after success or error");
+        let contents = std::fs::read_to_string(&output).unwrap();
+        if from_script && !allowed {
+            assert!(result.unwrap_err().to_string().contains("Allow Scripts to Write Files"));
+            assert_eq!(contents, "existing file", "blocked scripts must not replace an existing file");
+        } else {
+            assert_eq!(result.unwrap()["frames"], 3);
+            assert!(contents.contains("def import_scene():"));
+        }
+    }
+}
diff --git a/crates/engine/tests/blender_scene_oracle.py b/crates/engine/tests/blender_scene_oracle.py
new file mode 100644
index 000000000..3d1cbeda7
--- /dev/null
+++ b/crates/engine/tests/blender_scene_oracle.py
@@ -0,0 +1,61 @@
+"""Public-API oracle for scripts generated by src/tests/blender.rs; no Blender source dependency."""
+import json
+import math
+import runpy
+import sys
+
+import bpy
+from bpy_extras.object_utils import world_to_camera_view
+from mathutils import Quaternion, Vector
+
+path = sys.argv[sys.argv.index("--") + 1]
+before = set(bpy.data.scenes)
+exported = runpy.run_path(path, run_name="__main__")
+scene = exported["EFFECTCRAFT_SCENE"]
+data = exported["DATA"]
+assert before.issubset(set(bpy.data.scenes)), "existing scenes were removed"
+assert scene not in before
+assert scene.frame_start == 101 and scene.frame_end == 103
+assert abs(scene.render.fps / scene.render.fps_base - 30000 / 1001) < 1e-4
+assert (scene.render.resolution_x, scene.render.resolution_y) == (640, 360)
+camera = scene.camera
+assert camera.animation_data.action is not None
+assert camera.data.animation_data.action is not None
+assert camera.data.sensor_fit == 'HORIZONTAL'
+metadata = json.loads(bpy.data.texts[scene["effectcraft_metadata_text"]].as_string())
+assert metadata["solve"]["averageError"] == 0.12
+cloud = scene.objects["Solved Track Points"]
+assert len(cloud.data.vertices) == 2
+assert cloud.hide_render
+assert cloud.data.attributes["track_id"].data[0].value == 7
+assert any(obj.name.startswith("Solved Ground Plane") for obj in scene.objects)
+
+for i, sample in enumerate(data["frames"]):
+    scene.frame_set(sample["frame"])
+    bpy.context.view_layer.update()
+    assert abs(camera.data.lens - sample["lens"]) < 1e-5
+    assert abs(camera.data.dof.focus_distance - sample["focus"]) < 1e-5
+    assert abs(camera.data.dof.aperture_fstop - sample["fstop"]) < 1e-5
+    assert camera.data.dof.use_dof
+    assert (camera.location - Vector(sample["location"])).length < 1e-5
+    raw = data["solve"]["frames"][i]
+    rot = Vector(raw["rot"])
+    rotation = Quaternion(rot.normalized(), rot.length).to_matrix() if rot.length else Quaternion().to_matrix()
+    for vertex, point in zip(cloud.data.vertices, data["solve"]["points"]):
+        relative = rotation @ (Vector(point["pos"]) - Vector(raw["center"]))
+        expected = (raw["focal"] * relative.x / relative.z + 320,
+                    raw["focal"] * relative.y / relative.z + 180)
+        projected = world_to_camera_view(scene, camera, vertex.co)
+        actual = (projected.x * 640, (1.0 - projected.y) * 360)
+        assert math.dist(actual, expected) < 0.002, (sample["frame"], actual, expected)
+
+    if "Video not found" not in " ".join(data["warnings"]):
+        background = camera.data.background_images[0]
+        assert background.image.source == 'MOVIE'
+        assert tuple(background.image.size) == (640, 360)
+        user = background.image_user
+        actual_source = sample["frame"] - user.frame_start + user.frame_offset
+        assert actual_source == sample["sourceFrame"], (actual_source, sample["sourceFrame"])
+        assert user.use_auto_refresh
+
+print("EFFECTCRAFT_BLENDER_ORACLE_OK")
diff --git a/crates/ui-egui/src/i18n/ui.rs b/crates/ui-egui/src/i18n/ui.rs
index 061090871..23926864d 100644
--- a/crates/ui-egui/src/i18n/ui.rs
+++ b/crates/ui-egui/src/i18n/ui.rs
@@ -2996,6 +2996,7 @@ const UKRAINIAN: &[(&str, &str)] = &[
 
 // Brazilian Portuguese.
 const PORTUGUESE: &[(&str, &str)] = &[
+    ("Export Scene to Blender...", "Exportar cena para o Blender..."),
     ("   OK   ", "   OK   "),
     ("  Delete  ", "  Excluir  "),
     (" Open Auto-Save ", " Abrir salvamento automático "),
diff --git a/crates/ui-egui/src/menus/frontend.rs b/crates/ui-egui/src/menus/frontend.rs
index 5d65ffb8f..a5d616714 100644
--- a/crates/ui-egui/src/menus/frontend.rs
+++ b/crates/ui-egui/src/menus/frontend.rs
@@ -560,6 +560,7 @@ pub(super) fn file_dialog(app: &mut EffectcraftApp, id: &str, params: &Value) ->
         "anim.applyPreset" => ("path", Ask::Open(&["ecpreset", "json"])),
         "view.exportGuides" => ("path", Ask::Save("Guides.json")),
         "view.importGuides" => ("path", Ask::Open(&["json"])),
+        "camera.exportBlender" => ("path", Ask::Save("Tracked Scene.py")),
         "file.exportLottie" => ("path", Ask::Save("Animation.json")),
         "file.importLottie" => ("path", Ask::Open(&["json", "lottie"])),
         "file.importProject" => ("path", Ask::Open(&["ecproj", "ecprojx"])),
diff --git a/crates/ui-egui/src/panels/camera_tracker_ui.rs b/crates/ui-egui/src/panels/camera_tracker_ui.rs
index bca98ea4b..481577398 100644
--- a/crates/ui-egui/src/panels/camera_tracker_ui.rs
+++ b/crates/ui-egui/src/panels/camera_tracker_ui.rs
@@ -430,6 +430,11 @@ pub fn editor(
             actions.push(("camera.create".into(), me.clone()));
         }
         app.auto.add(&format!("effectControls.cameraTracker.{}.createCamera", g.uid), b3, "Create Camera");
+        let export = Rect::from_min_size(pos2(r.min.x + 24.0, r.min.y + 70.0), vec2(218.0, 22.0));
+        if widgets::text_button(ui, export, tr("Export Scene to Blender..."), false, &t, egui::Id::unique(("ct-blender", g.uid))).clicked() && !busy {
+            actions.push(("camera.exportBlender".into(), me.clone()));
+        }
+        app.auto.add(&format!("effectControls.cameraTracker.{}.exportBlender", g.uid), export, "Export Scene to Blender...");
     }
     let status = match app.session.camera_progress() {
         Some(pr) if running => pr.banner(),
@@ -457,4 +462,4 @@ pub fn editor(
 }
 
 /// Height of [`editor`].
-pub const EDITOR_HEIGHT: f32 = 68.0;
+pub const EDITOR_HEIGHT: f32 = 100.0;
diff --git a/crates/ui-egui/tests/it/ui_camera_tracker.rs b/crates/ui-egui/tests/it/ui_camera_tracker.rs
index f7d349342..8c4be61a7 100644
--- a/crates/ui-egui/tests/it/ui_camera_tracker.rs
+++ b/crates/ui-egui/tests/it/ui_camera_tracker.rs
@@ -16,8 +16,9 @@ const H: f64 = 360.0;
 
 fn app() -> (EffectcraftApp, u64, u64) {
     let mut s = Session::default();
-    s.execute("comp.new", json!({"name": "Shot", "width": W, "height": H, "duration": 2})).unwrap();
-    let plate = s.execute("layer.newSolid", json!({"name": "Plate", "color": "#406080"})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Shot", "width": W as u32, "height": H as u32, "duration": 2, "frameRate": 30})).unwrap();
+    let plate =
+        s.execute("layer.newSolid", json!({"name": "Plate", "color": "#406080", "width": W as u32, "height": H as u32})).unwrap()["layer"].as_u64().unwrap();
     let r = s.execute("effect.apply", json!({"effect": ct::ID, "layers": [plate]})).unwrap();
     let uid = r["effects"][0].as_u64().unwrap();
     // A synthetic solve: a static camera (focal 600) looking at a 6 × 4 grid of points on z = 1.
@@ -135,7 +136,11 @@ fn viewer_points_selection_and_effect_controls() {
     h.state_mut().show_panel(PanelKind::EffectControls);
     h.run_steps(4);
     let all = ids(&h);
-    for want in [format!("effectControls.cameraTracker.{uid}.analyze"), format!("effectControls.cameraTracker.{uid}.createCamera")] {
+    for want in [
+        format!("effectControls.cameraTracker.{uid}.analyze"),
+        format!("effectControls.cameraTracker.{uid}.createCamera"),
+        format!("effectControls.cameraTracker.{uid}.exportBlender"),
+    ] {
         assert!(all.contains(&want), "missing {want}");
     }
     // Tracker panel: Track Camera is available for the selected layer.
@@ -145,6 +150,56 @@ fn viewer_points_selection_and_effect_controls() {
     assert!(h.state().session.is_enabled("track.camera"));
 }
 
+#[test]
+fn blender_export_button_opens_python_dialog_and_writes_scene() {
+    use effectcraft_engine::project::{Footage, FootageKind, ItemKind, LayerId, LayerSource};
+    let (mut a, plate, uid) = app();
+    let cid = a.session.active_comp_id().unwrap();
+    a.session
+        .edit("video fixture", None, |p, _| {
+            let item = p.add_item(
+                "Video",
+                Default::default(),
+                None,
+                ItemKind::Footage(Footage {
+                    path: "/tmp/effectcraft-ui-synthetic.mp4".into(),
+                    kind: FootageKind::Video,
+                    width: W as u32,
+                    height: H as u32,
+                    has_video: true,
+                    duration: effectcraft_engine::time::Tick::from_seconds_f64(2.0),
+                    ..Default::default()
+                }),
+            );
+            p.comp_mut(cid).unwrap().layer_mut(LayerId(plate)).unwrap().source = LayerSource::Footage { item };
+            Ok(())
+        })
+        .unwrap();
+    a.session.camera_pending.clear();
+    let output = std::env::temp_dir().join(format!("effectcraft-ui-blender-{}.py", std::process::id()));
+    let selected_path = output.clone();
+    a.hooks.pick_save_file = Some(Box::new(move |name, ext| {
+        assert!(name.ends_with(".py"));
+        assert_eq!(ext, "py");
+        Some(selected_path.to_string_lossy().into_owned())
+    }));
+    let shot = std::env::var("EFFECTCRAFT_BLENDER_UI_SNAPSHOT").ok();
+    let builder = Harness::builder().with_size(egui::vec2(1600.0, 1000.0));
+    let builder = if shot.is_some() { builder.wgpu() } else { builder };
+    let mut h = builder.build_eframe(|_| a);
+    h.state_mut().show_panel(PanelKind::EffectControls);
+    h.run_steps(5);
+    let button = rect(&h, &format!("effectControls.cameraTracker.{uid}.exportBlender"));
+    if let Some(path) = shot {
+        h.render().expect("render export button").save(path).unwrap();
+    }
+    click(&mut h, button.center(), Default::default());
+    assert!(output.exists(), "UI export failed: {}", h.state().ui.status);
+    let script = std::fs::read_to_string(output).expect("clicking the export button saves a Python scene");
+    assert!(script.contains("def import_scene():"));
+    assert_eq!(h.state().session.active_comp().unwrap().layers.len(), 1, "export does not create a camera in the source project");
+}
+
 /// Drag with `button` from `from` to `to` in steps, then release.
 fn drag_with(h: &mut Harness<'_, EffectcraftApp>, button: egui::PointerButton, from: egui::Pos2, to: egui::Pos2) {
     h.input_mut().events.push(egui::Event::PointerMoved(from));
diff --git a/docs/agents.md b/docs/agents.md
index 172e5c4c6..8c2d49a45 100644
--- a/docs/agents.md
+++ b/docs/agents.md
@@ -446,7 +446,12 @@ and Origin), `camera.createFromSolve {kind: text|solid|null|shadowCatcher, point
 {center, normal, size?}, multiple?}` (Create Text / Solid / Null / Shadow Catcher, Camera and Light,
 Create Multiple …), `camera.deletePoints {points?, wait?}` (re-solves; with Auto-delete Points
 Across Time the same feature's other tracks go too) and `camera.create` (the Create Camera button).
-Each is one undo step; the first create adds the one-node "3D Tracker Camera" keyed on every frame.
+Each edit is one undo step; the first create adds the one-node "3D Tracker Camera" keyed on every frame.
+
+`camera.exportBlender {path: ".py", layer?, effect?, sensorWidth?: 36, unitScale?: 0.01,
+startFrame?: 1, includePoints?: true}` exports the solve as an executable Blender scene script:
+baked camera/lens/focus, synced video background, points and ground. See
+[Blender camera export](blender-camera-export.md) for framing, assumptions and limitations.
 Changing the layer's frames clears the analysis; changing `effects/#1/shotType`,
 `effects/#1/horizontalAngleOfView`, `effects/#1/advanced/solveMethod` re-solves the stored tracks.
 
diff --git a/docs/blender-camera-export.md b/docs/blender-camera-export.md
new file mode 100644
index 000000000..d102eef4f
--- /dev/null
+++ b/docs/blender-camera-export.md
@@ -0,0 +1,101 @@
+# Exporting a tracked camera to Blender
+
+After the **3D Camera Tracker** finishes solving, click **Export Scene to Blender...** in its
+Effect Controls and save the `.py` file. In Blender 4.0 or newer, open it in the Scripting
+workspace's Text Editor and choose **Run Script**. The script creates and activates a new scene;
+it preserves existing scenes and objects. Save the resulting `.blend` normally.
+
+The script uses Blender's public Python API, with no add-on or Python dependencies beyond
+Blender itself. For unattended use: `blender --background --python "Tracked Scene.py"`.
+That imports the scene in memory; it does not automatically save a `.blend`.
+
+## Transferred data
+
+- Camera position and quaternion rotation baked on every analyzed frame, with consistent
+  quaternion signs and linear interpolation; zoom/lens animation, including Variable Zoom.
+- Tracking input/video resolution, horizontal sensor fit, exact rational composition FPS,
+  frame range and composition markers within the analyzed interval. The first analyzed frame
+  becomes Blender frame 1 by default; the original composition timestamps remain in metadata.
+- The original video or still as the camera's background image, at full opacity, refreshed on
+  frame changes. Source-frame offsets are baked too, accounting for trim, stretch, source FPS
+  and Time Remap. This is a viewport background, not a render/compositor background.
+- Focus distance, DOF switch, f-stop, iris blade count, rotation and aspect sampled from the
+  tracker's linked **3D Tracker Camera**, including keyframes and expressions. Create that
+  camera and adjust its Camera Options before exporting to transfer custom focus settings.
+- Solved 3D points as a non-rendering vertex mesh, with point attributes for track ID,
+  reprojection error and first/last visible frame. A chosen ground plane becomes Blender's XY
+  plane, with its origin preserved and a non-rendering wire plane as a placement guide.
+- Shutter duration (not automatically enabled), plus the original shutter phase in metadata.
+- A Blender Text datablock named `EffectCraft Tracking Metadata.json` containing the complete
+  solve, optional original 2D tracks, per-frame timings, source interpretation, diagnostics and
+  export warnings. Radial distortion coefficients are also camera custom properties.
+
+Coordinates are converted from EffectCraft's right/down/forward world to Blender's
+right/forward/up world, including the camera's local up and negative-Z viewing direction.
+Export uses the tracking input's framing, not the footage layer's final 2D placement in the
+composition. Camera pose and lens always come from the solve; subsequent manual pose/lens edits
+on the linked camera are not substituted for the tracked motion.
+
+## What cannot be inferred
+
+Monocular tracking cannot recover absolute scene scale, physical sensor size, optical focus,
+f-stop or exposure from feature tracks. The default sensor width is an assumption of **36 mm**;
+the focal length in millimeters is derived from it while preserving the solved field of view.
+The default scale is **0.01 Blender units per composition-world pixel**, not a measurement.
+Without a linked camera, DOF is disabled and focus distance uses the default solved scene depth.
+Blender's physical DOF approximates EffectCraft's blur model: Blur Level and Iris Roundness are
+retained in metadata, but have no direct Blender equivalent.
+
+Brown-model radial `k1`/`k2` coefficients use radius normalized to half the image diagonal.
+They are preserved, **not** assigned to Blender's different lens-distortion model. For a precise
+match when distortion is nonzero, use an undistorted plate; the script prints a warning.
+The tracker assumes square pixels, so Blender renders square pixels; any non-square source
+interpretation is retained in metadata and flagged.
+
+The `.py` references the video; it does not contain a copy of the video's bytes. When moving it,
+keep the video next to the script (same filename), or relink the background image in Blender.
+Missing/unsupported media produces a warning while retaining the imported camera and geometry.
+Masks and effects applied before the tracker are not baked into the original media. Export
+requires a direct video/still footage layer at the analyzed size; render precomps, sequences or
+size-changing preprocessing to a video and track that video first.
+
+## Agent / control-channel command
+
+```json
+{
+  "command": "camera.exportBlender",
+  "params": {
+    "layer": "#1",
+    "path": "/output/Tracked Scene.py",
+    "sensorWidth": 36,
+    "unitScale": 0.01,
+    "startFrame": 1,
+    "includePoints": true
+  }
+}
+```
+
+`comp`, `layer` and `effect` select the tracker as with `camera.analyze`. Without explicit
+selection, the selected tracker (or first tracker in the composition) is used. `sensorWidth`,
+`unitScale`, `startFrame` and `includePoints` are optional. The reply contains file size,
+exported frame/point counts and warnings. Writing uses the host's atomic file service.
+Calls issued by scripts require **Allow Scripts to Write Files and Access Network** in
+Settings ▸ Scripting & Expressions. Export from the UI or control channel remains available
+with that preference off.
+
+Export is limited to 100,000 analyzed frames, 100,000 points and 64 MiB of serialized scene data;
+invalid, stale or incomplete solves return an actionable error without modifying the document.
+
+## Verification
+
+Engine tests check argument validation, escaped/Unicode paths, fractional FPS, trim/stretch,
+focus/f-stop, zoom, ground placement, malformed solves and write failures. To additionally run
+the generated artifact against an installed Blender's public API:
+
+```sh
+EFFECTCRAFT_BLENDER=/path/to/blender cargo test -p effectcraft-engine tests::blender -- --nocapture
+```
+
+Optionally set `EFFECTCRAFT_BLENDER_PLATE` to a local synthetic 640×360 video to exercise media
+loading and source-frame offsets. The oracle checks every synthetic point's projection through
+the imported camera on every frame, as well as animation, DOF, timing and scene preservation.

From e2b56f1ba52b654c716107fdd75715f8a60d506a Mon Sep 17 00:00:00 2001
From: Krueels <90205419+Krueels@users.noreply.github.com>
Date: Thu, 29 Oct 2026 18:05:17 -0300
Subject: [PATCH 04/13] #986: remove personal credit from generated Blender
 scripts

---
 crates/engine/src/cmd/blender_scene.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/crates/engine/src/cmd/blender_scene.py b/crates/engine/src/cmd/blender_scene.py
index 7240cb1ca..9f8a522c5 100644
--- a/crates/engine/src/cmd/blender_scene.py
+++ b/crates/engine/src/cmd/blender_scene.py
@@ -1,5 +1,4 @@
 # EffectCraft camera tracker → Blender, original code under MIT OR Apache-2.0.
-# Blender scene export contributor: Krueels — https://github.com/Krueels
 # Run in Blender's Scripting workspace (Open, Run Script), or:
 # blender --background --python "Tracked Scene.py"
 # Creates a NEW scene; existing scenes and objects are preserved. Save the .blend yourself.

From 73817dc3f0c37ccbf639add2f54925322dc40bea Mon Sep 17 00:00:00 2001
From: Krueels <90205419+Krueels@users.noreply.github.com>
Date: Thu, 29 Oct 2026 19:28:04 -0300
Subject: [PATCH 05/13] #986: confine Blender exports and trim generated header

---
 crates/automation/src/confine.rs       |  1 +
 crates/automation/src/tests.rs         | 27 ++++++++++++++++++++++++++
 crates/engine/src/cmd/blender_scene.py |  3 +--
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/crates/automation/src/confine.rs b/crates/automation/src/confine.rs
index 67e5aef98..dc64084d3 100644
--- a/crates/automation/src/confine.rs
+++ b/crates/automation/src/confine.rs
@@ -97,6 +97,7 @@ const MIXED_WRITES: &[(&str, &[&str])] = &[("templates.create", &["projectPath",
 
 /// Commands that write files named by these parameters.
 const WRITES: &[(&str, &[&str])] = &[
+    ("camera.exportBlender", &["path"]),
     ("file.save", &["path"]),
     ("file.saveAs", &["path"]),
     ("file.saveCopy", &["path"]),
diff --git a/crates/automation/src/tests.rs b/crates/automation/src/tests.rs
index 560a527c7..49f0389f6 100644
--- a/crates/automation/src/tests.rs
+++ b/crates/automation/src/tests.rs
@@ -1473,3 +1473,30 @@ fn automation_roots_refuse_running_script_code() {
     call_json(&mut s, "execute_command", json!({"command": "scriptui.list"}));
     let _ = std::fs::remove_dir_all(&base);
 }
+
+#[test]
+fn blender_export_requires_an_absolute_path_in_a_write_root() {
+    use crate::confine::Confinement;
+    let base = std::env::temp_dir().join(format!("ec-blender-confine-{}", std::process::id()));
+    let (read, write) = (base.join("read"), base.join("write"));
+    for dir in [&read, &write] {
+        std::fs::create_dir_all(dir).unwrap();
+    }
+    let confinement = Confinement::new(std::slice::from_ref(&read), std::slice::from_ref(&write)).unwrap();
+    let check = |path: &std::path::Path| confinement.check_command("camera.exportBlender", &json!({"path": path}));
+    assert_eq!(check(&write.join("scene.py")).unwrap(), None);
+    for path in [read.join("scene.py"), base.join("outside.py"), write.join("../read/scene.py")] {
+        assert!(check(&path).is_err(), "must deny {}", path.display());
+    }
+    for path in ["scene.py", "./scene.py", "write/scene.py", "../scene.py"] {
+        let error = check(std::path::Path::new(path)).unwrap_err().to_string();
+        assert!(error.contains("give an absolute path"), "{path}: {error}");
+    }
+    let read_only = Confinement::new(std::slice::from_ref(&write), &[]).unwrap();
+    assert!(read_only.check_command("camera.exportBlender", &json!({"path": write.join("scene.py")})).is_err());
+    for path in [json!(read.join("scene.py")), json!("scene.py"), json!("$1.path")] {
+        let batch = json!({"steps": [{"command": "camera.exportBlender", "params": {"path": path}}]});
+        assert!(confinement.check_command("engine.batch", &batch).is_err());
+    }
+    std::fs::remove_dir_all(&base).unwrap();
+}
diff --git a/crates/engine/src/cmd/blender_scene.py b/crates/engine/src/cmd/blender_scene.py
index 9f8a522c5..0a9700a00 100644
--- a/crates/engine/src/cmd/blender_scene.py
+++ b/crates/engine/src/cmd/blender_scene.py
@@ -2,8 +2,7 @@
 # Run in Blender's Scripting workspace (Open, Run Script), or:
 # blender --background --python "Tracked Scene.py"
 # Creates a NEW scene; existing scenes and objects are preserved. Save the .blend yourself.
-# Public API references: https://docs.blender.org/api/4.5/bpy.types.Camera.html
-# https://docs.blender.org/api/4.5/bpy.types.ImageUser.html
+# Public API types: bpy.types.Camera, bpy.types.ImageUser
 import json
 import math
 import os

From 63ec5f2aad6d865cd3cb75428a1f222e32753252 Mon Sep 17 00:00:00 2001
From: erythrofr <20369086+erythrofr@users.noreply.github.com>
Date: Fri, 30 Oct 2026 00:39:56 +0100
Subject: [PATCH 06/13] Export: apply crop once when calculating resize
 dimensions

Calculate frame_size from the original rendered dimensions and effective
render scale before cropping, so locked-aspect resize does not apply the
crop margins a second time in its dimension calculation.

Add dimension and decoded-PNG regressions for crop, resize, padding, scaled
ROI, both interpolation qualities, and zero or extreme requested sizes.

AI assistance: OpenAI Codex (GPT-6).
---
 crates/export/src/pipeline.rs             | 84 ++++++++++++++++++++++-
 crates/export/tests/it/render_settings.rs | 23 +++++++
 2 files changed, 106 insertions(+), 1 deletion(-)

diff --git a/crates/export/src/pipeline.rs b/crates/export/src/pipeline.rs
index c639ebad1..7b9e4111c 100644
--- a/crates/export/src/pipeline.rs
+++ b/crates/export/src/pipeline.rs
@@ -431,12 +431,13 @@ impl<'a> Cx<'a> {
     fn crop_resize(&self, img: Image) -> Image {
         let om = self.job.output;
         let scale = self.comp().map(|c| self.job.settings.effective_scale(c)).unwrap_or_else(|| self.job.settings.resolution.clamp(0.01, 4.0));
+        // frame_size applies crop itself: use the original frame and the same scale as edges.
+        let (w, h) = om.frame_size(img.width, img.height, scale);
         let (t, l, b, r) = om.crop.edges(img.width, img.height, scale);
         let img = if (t, l, b, r) == (0, 0, 0, 0) { img } else { crop(&img, t, l, b, r) };
         if !om.resize.enabled {
             return img;
         }
-        let (w, h) = om.frame_size(img.width, img.height, 1.0);
         if (w, h) == (img.width, img.height) {
             return img;
         }
@@ -1062,6 +1063,87 @@ mod tests {
         }
     }
 
+    #[test]
+    fn crop_resize_applies_margins_once() {
+        use effectcraft_project::render_queue::{Crop, OutputModule, Resize};
+        let output = OutputModule {
+            crop: Crop { enabled: true, left: 480, right: 480, ..Default::default() },
+            resize: Resize { enabled: true, width: 1280, lock_aspect: true, quality: ResizeQuality::Low, ..Default::default() },
+            ..Default::default()
+        };
+        assert_eq!(output.frame_size(1920, 1080, 1.0), (1280, 1440));
+        let img = run_crop_resize(Image::new(1920, 1080), &output, 1.0);
+        assert_eq!((img.width, img.height), (1280, 1440));
+        assert_eq!(img.data.len(), 1280 * 1440);
+    }
+
+    fn run_crop_resize(img: Image, output: &effectcraft_project::render_queue::OutputModule, scale: f64) -> Image {
+        use effectcraft_project::render_queue::RenderSettings;
+        let project = Project::default();
+        let settings = RenderSettings { resolution: scale, ..Default::default() };
+        let job = Job {
+            project: &project,
+            footage: &effectcraft_render::NoFootage,
+            expr: None,
+            accel: None,
+            comp: effectcraft_project::ItemId(0),
+            settings: &settings,
+            output,
+            path: "unused.png",
+            sink: None,
+            nested_switches: true,
+            options: Default::default(),
+        };
+        Cx::new(&job).crop_resize(img)
+    }
+
+    #[test]
+    fn crop_resize_dimensions_match_the_output_module() {
+        use effectcraft_project::render_queue::{Crop, OutputModule, Resize};
+        let edges = Crop { enabled: true, left: 2, right: 2, ..Default::default() };
+        let padding = Crop { enabled: true, left: -2, bottom: -2, ..Default::default() };
+        let roi = |rect| Crop { enabled: true, use_roi: true, roi: Some(rect), ..Default::default() };
+        for quality in [ResizeQuality::Low, ResizeQuality::High] {
+            let resize = |width| Resize { enabled: true, width, height: 1, lock_aspect: true, quality };
+            for (crop, resize, scale, expected) in [
+                (Crop::default(), Resize::default(), 1.0, (8, 6)),
+                (edges, Resize::default(), 1.0, (4, 6)),
+                (Crop::default(), resize(4), 1.0, (4, 3)),
+                (edges, resize(8), 1.0, (8, 12)),
+                (padding, resize(5), 1.0, (5, 4)),
+                (roi([4.0, 2.0, 8.0, 6.0]), resize(8), 0.5, (8, 6)),
+                (roi([1.0, 0.5, 2.0, 1.5]), resize(8), 2.0, (8, 6)),
+                (edges, Resize { lock_aspect: false, height: 2, ..resize(5) }, 1.0, (5, 2)),
+            ] {
+                let output = OutputModule { crop, resize, ..Default::default() };
+                assert_eq!(output.frame_size(8, 6, scale), expected);
+                let img = run_crop_resize(Image::filled(8, 6, [0.25, 0.0, 0.0, 0.5]), &output, scale);
+                assert_eq!((img.width, img.height), expected, "{crop:?}, {resize:?}, scale {scale}");
+                assert_eq!(img.data.len(), expected.0 as usize * expected.1 as usize);
+            }
+        }
+    }
+
+    #[test]
+    fn crop_resize_zero_and_extreme_sizes_stay_bounded() {
+        use effectcraft_project::render_queue::{Crop, OutputModule, Resize};
+        for quality in [ResizeQuality::Low, ResizeQuality::High] {
+            for (size, crop, width, height, expected) in [
+                ((8, 6), Crop::default(), 0, 0, (1, 1)),
+                ((8, 1), Crop::default(), u32::MAX, 1, (30_000, 1)),
+                ((1, 8), Crop::default(), 1, u32::MAX, (1, 30_000)),
+                ((8, 6), Crop { enabled: true, left: 20_000, right: 20_000, ..Default::default() }, 2, 3, (2, 3)),
+                ((0, 0), Crop { enabled: true, left: 1, top: 1, ..Default::default() }, 2, 3, (2, 3)),
+            ] {
+                let output = OutputModule { crop, resize: Resize { enabled: true, width, height, lock_aspect: false, quality }, ..Default::default() };
+                let img = run_crop_resize(Image::new(size.0, size.1), &output, 1.0);
+                assert_eq!((img.width, img.height), expected);
+                assert_eq!(img.data.len(), expected.0 as usize * expected.1 as usize);
+                assert!(img.data.iter().all(|p| *p == [0.0; 4]));
+            }
+        }
+    }
+
     #[test]
     fn crop_and_pad() {
         let mut img = Image::new(4, 3);
diff --git a/crates/export/tests/it/render_settings.rs b/crates/export/tests/it/render_settings.rs
index 465d8e5fe..c2d7dcbfa 100644
--- a/crates/export/tests/it/render_settings.rs
+++ b/crates/export/tests/it/render_settings.rs
@@ -174,6 +174,29 @@ fn crop_roi_and_resize() {
     assert_eq!((z.width(), z.height()), (32, 24));
 }
 
+#[test]
+fn crop_resize_preserves_pixels_when_the_cropped_size_is_requested() {
+    let (p, cid) = project(FrameRate::new(25, 1), |_, _| {});
+    for (crop, scale, expected) in [
+        (Crop { enabled: true, left: 16, right: 16, ..Default::default() }, 1.0, (32, 48)),
+        (Crop { enabled: true, left: -4, top: -2, ..Default::default() }, 1.0, (68, 50)),
+        (Crop { enabled: true, use_roi: true, roi: Some([0.0, 24.0, 32.0, 24.0]), ..Default::default() }, 0.5, (16, 12)),
+        (Crop { enabled: true, use_roi: true, roi: Some([0.0, 24.0, 32.0, 24.0]), ..Default::default() }, 2.0, (64, 48)),
+    ] {
+        let settings = RenderSettings { resolution: scale, ..custom(0.4, 0.44) };
+        let mut output = OutputModule { crop, ..OutputModule::for_format(OutputFormat::PngSequence) };
+        let reference = png(&run(&p, cid, &settings, &output, "/c/reference_[#####].png"), 0);
+        assert_eq!(reference.dimensions(), expected);
+        assert!(reference.pixels().any(|p| p.0[0] > 150), "the reference contains visible content");
+        for quality in [ResizeQuality::Low, ResizeQuality::High] {
+            output.resize = Resize { enabled: true, width: expected.0, height: 1, lock_aspect: true, quality };
+            let actual = png(&run(&p, cid, &settings, &output, "/c/resized_[#####].png"), 0);
+            assert_eq!(actual.dimensions(), expected);
+            assert!(actual == reference, "crop {crop:?}, scale {scale}, quality {quality:?}: pixels changed");
+        }
+    }
+}
+
 #[test]
 fn alpha_only_and_premultiplied() {
     let (p, cid) = project(FrameRate::new(25, 1), |p, comp| {

From 3bc1caaedbf53dac566ecd677b84d9400bae18ae Mon Sep 17 00:00:00 2001
From: Camille Moine <ki2pixel@gmail.com>
Date: Mon, 19 Oct 2026 19:54:11 +0200
Subject: [PATCH 07/13] Shapes: per-corner roundness for Rectangle Path (#1896)

Add Per-Corner Roundness to Rectangle Path: a checkbox (off by default) and four Pixels properties (top-left, top-right, bottom-right, bottom-left). New rectangles initialise the four values from their Roundness, so ticking the box keeps the shape; the radii are animatable and expression-driven.\n\nrect_radii() builds the path clockwise from the top-left with kappa quarter-circle arcs. Overlapping radii scale down like CSS border-radius; negative and non-finite radii are square; rect() delegates to it, so uniform roundness clamps to half the shorter side as before.\n\nLottie rc has one r: four equal static radii export as that value; mixed or animated radii export roundness 0 with a warning. Import puts r into the four per-corner values so ticking the box on an imported rectangle keeps the shape.\n\nTests: path geometry and clamping, rendered per-corner pixels, Lottie equal/mixed/checkbox-off export.
---
 crates/engine/src/cmd/paths.rs                | 65 +++++++++++-----
 crates/engine/src/tests/stubs.rs              | 64 +++++++++++++++
 crates/lottie/src/shapes.rs                   | 22 +++++-
 crates/lottie/src/tests.rs                    | 36 +++++++++
 crates/path/src/lib.rs                        | 77 +++++++++++++++++++
 crates/project/src/build.rs                   |  7 ++
 crates/render/src/shapes.rs                   | 15 +++-
 crates/render/src/shapes/tests.rs             | 30 ++++++++
 crates/ui-egui/src/panels/timeline/tests.rs   |  5 ++
 crates/ui-egui/tests/it/ui_timeline_shapes.rs |  5 ++
 10 files changed, 304 insertions(+), 22 deletions(-)

diff --git a/crates/engine/src/cmd/paths.rs b/crates/engine/src/cmd/paths.rs
index 0bb2eaae2..7cd457640 100644
--- a/crates/engine/src/cmd/paths.rs
+++ b/crates/engine/src/cmd/paths.rs
@@ -5,6 +5,7 @@
 use effectcraft_keyframe::{ShapePath, Value as KV};
 use effectcraft_project::build::{self, Ids};
 use effectcraft_project::{FeatherFalloff, GroupKind, ItemId, LayerId, LayerSource, MaskMotionBlur, Node, PropGroup, Uid};
+use effectcraft_render::EvalCtx;
 use serde_json::{Value, json};
 
 use super::layer_menu::target_masks;
@@ -111,18 +112,30 @@ fn roto_bezier(s: &mut Session, p: &Value) -> Result<Value> {
 /// The parametric shape paths that Convert To Bezier Path replaces with an editable path.
 const PARAMETRIC: [&str; 3] = ["rect", "ellipse", "star"];
 
-/// The path a parametric shape group draws, in the group's own space, read at `lt`. This is the
-/// geometry the renderer builds from the same values (`render::shapes::collect`), so the converted
-/// path is the shape that was on screen rather than an approximation of it; the defaults match
-/// that code for a property a group doesn't carry (a polygon has no inner radius or roundness).
-fn parametric_path(g: &PropGroup, lt: effectcraft_time::Tick) -> Option<ShapePath> {
-    let f = |id: &str, d: f64| g.prop(id).map_or(d, |pr| pr.value_at(lt).as_f64());
-    let v2 = |id: &str, d: [f64; 2]| g.prop(id).map_or(d, |pr| pr.value_at(lt).as_vec2());
+/// The path a parametric shape group draws, in the group's own space. This is the geometry the
+/// renderer builds from the same values (`render::shapes::collect`), expressions included, so the
+/// converted path is the shape that was on screen rather than an approximation of it; the defaults
+/// match that code for a property a group doesn't carry (a polygon has no inner radius or
+/// roundness).
+fn parametric_path(ctx: &EvalCtx, layer: &effectcraft_project::Layer, g: &PropGroup) -> Option<ShapePath> {
+    let f = |id: &str, d: f64| ctx.f(layer, g, id, d);
+    let v2 = |id: &str, d: [f64; 2]| ctx.v2(layer, g, id, d);
     let path = match g.match_id.as_str() {
-        "rect" => effectcraft_path::rect(v2("size", [100.0; 2]), v2("position", [0.0; 2]), f("roundness", 0.0)),
+        "rect" => {
+            let (size, pos) = (v2("size", [100.0; 2]), v2("position", [0.0; 2]));
+            if ctx.b(layer, g, "perCorner") {
+                effectcraft_path::rect_radii(
+                    size,
+                    pos,
+                    [f("topLeftRoundness", 0.0), f("topRightRoundness", 0.0), f("bottomRightRoundness", 0.0), f("bottomLeftRoundness", 0.0)],
+                )
+            } else {
+                effectcraft_path::rect(size, pos, f("roundness", 0.0))
+            }
+        }
         "ellipse" => effectcraft_path::ellipse(v2("size", [100.0; 2]), v2("position", [0.0; 2])),
         "star" => effectcraft_path::polystar(effectcraft_path::Polystar {
-            star: g.prop("type").map_or(0, |pr| pr.value_at(lt).as_enum()) == 0,
+            star: ctx.e(layer, g, "type") == 0,
             points: f("points", 5.0),
             pos: v2("position", [0.0; 2]),
             rotation: f("rotation", 0.0),
@@ -160,28 +173,40 @@ fn convert_to_bezier(s: &mut Session, p: &Value) -> Result<Value> {
     }
     let t = s.time();
     let n = shapes.len();
+    // Read the geometry before editing, with the same expression-aware context the renderer
+    // uses: an expression-driven corner radius, size or position must convert to what is on
+    // screen, not to the property's underlying value.
+    let expr = s.expr.clone();
+    let prepared = {
+        let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
+        let ctx =
+            EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: expr.as_deref(), footage: None, property_overrides: &[], media_overrides: &[] };
+        let mut prepared = Vec::new();
+        for (lid, uid) in &shapes {
+            let Some(l) = comp.layer(*lid) else { continue };
+            let Some(old) = l.props.sub("contents").and_then(|c| c.find_group(*uid)) else { continue };
+            let Some(path) = parametric_path(&ctx, l, old) else { continue };
+            // Path Direction is the shape's own, not a default: reversing is a separate command.
+            prepared.push((*lid, *uid, path, ctx.e(l, old, "direction"), old.enabled));
+        }
+        prepared
+    };
     let made = s.edit("Convert To Bezier Path", None, |proj, st| {
         let mut next = proj.next_id;
         let mut made = Vec::new();
-        for (lid, uid) in &shapes {
-            let l = layer_mut(proj, cid, *lid)?;
-            let lt = l.layer_time(t);
+        for (lid, uid, path, direction, enabled) in prepared {
+            let l = layer_mut(proj, cid, lid)?;
             let contents = l.props.sub_mut("contents").ok_or_else(|| bad("path.convertToBezier", "not a shape layer"))?;
-            let Some(old) = contents.find_group(*uid) else { continue };
-            let Some(path) = parametric_path(old, lt) else { continue };
-            // Path Direction is the shape's own, not a default: reversing is a separate command.
-            let direction = old.prop("direction").map_or(0, |pr| pr.value_at(lt).as_enum());
-            let enabled = old.enabled;
             let mut g = build::shape_path(&mut Ids(&mut next), path);
             if let Some(pr) = g.prop_mut("direction") {
                 pr.value = KV::Enum(direction);
             }
             g.enabled = enabled;
             let new_uid = g.uid;
-            let parent = contents.parent_of_mut(*uid).ok_or_else(|| bad("path.convertToBezier", "no such shape item"))?;
-            let Some(at) = parent.children.iter().position(|c| c.uid() == *uid) else { continue };
+            let parent = contents.parent_of_mut(uid).ok_or_else(|| bad("path.convertToBezier", "no such shape item"))?;
+            let Some(at) = parent.children.iter().position(|c| c.uid() == uid) else { continue };
             parent.children[at] = Node::Group(g);
-            made.push((*lid, new_uid));
+            made.push((lid, new_uid));
         }
         proj.next_id = next;
         // The new paths are what is selected, so the vertices can be edited straight away.
diff --git a/crates/engine/src/tests/stubs.rs b/crates/engine/src/tests/stubs.rs
index 9735f2c08..087a4ae1a 100644
--- a/crates/engine/src/tests/stubs.rs
+++ b/crates/engine/src/tests/stubs.rs
@@ -585,6 +585,70 @@ fn convert_to_bezier_reads_the_shape_as_it_is_set() {
     assert!((mid(&xs) - 10.0).abs() < 1e-6 && (mid(&ys) - 5.0).abs() < 1e-6, "centred on the position: {:?} {:?}", mid(&xs), mid(&ys));
 }
 
+/// #1896: Convert To Bezier Path reads Per-Corner Roundness, not just the uniform Roundness, so
+/// the editable path is the shape that was on screen.
+#[test]
+fn convert_to_bezier_honours_per_corner_roundness() {
+    let mut s = comp();
+    let l = s.execute("layer.newShape", json!({"kind": "rect", "size": [120, 80]})).unwrap()["layer"].as_u64().unwrap();
+    let (uid, _) = first_shape(&s, l);
+    let uid_of = |s: &Session, id: &str| layer(s, l).props.sub("contents").unwrap().find_group(uid).unwrap().get(id).unwrap().uid;
+    let per_corner = uid_of(&s, "perCorner");
+    let top_left = uid_of(&s, "topLeftRoundness");
+    let bottom_right = uid_of(&s, "bottomRightRoundness");
+    for (u, v) in [(per_corner, json!(true)), (top_left, json!(20.0)), (bottom_right, json!(10.0))] {
+        s.execute("prop.set", json!({"layer": l, "path": format!("@{u}"), "value": v})).unwrap();
+    }
+
+    s.state.selected_props = vec![(LayerId(l), uid)];
+    s.execute("path.convertToBezier", json!({})).unwrap();
+    let (new_uid, now) = first_shape(&s, l);
+    assert_eq!(now, "path");
+    let path = shape_path_of(&s, l, new_uid);
+    let expected = effectcraft_path::from_kurbo(&effectcraft_path::rect_radii([120.0, 80.0], [0.0, 0.0], [20.0, 0.0, 10.0, 0.0])).into_iter().next().unwrap();
+    assert_eq!(path, expected, "the converted path has the per-corner geometry");
+}
+
+/// #1896: Convert To Bezier Path evaluates the shape's expressions, so an expression-driven
+/// Per-Corner checkbox and radius convert to the geometry on screen.
+#[test]
+fn convert_to_bezier_evaluates_corner_expressions() {
+    struct Corners;
+    impl effectcraft_render::ExprHost for Corners {
+        fn eval(
+            &self,
+            _: &effectcraft_render::EvalCtx,
+            _: &effectcraft_project::Layer,
+            prop: &effectcraft_project::Property,
+            value: &KV,
+        ) -> std::result::Result<KV, String> {
+            Ok(match prop.match_id.as_str() {
+                "perCorner" => KV::Bool(true),
+                "topLeftRoundness" => KV::Scalar(20.0),
+                _ => value.clone(),
+            })
+        }
+    }
+
+    let mut s = comp();
+    s.expr = Some(Arc::new(Corners));
+    let l = s.execute("layer.newShape", json!({"kind": "rect", "size": [120, 80]})).unwrap()["layer"].as_u64().unwrap();
+    let (uid, _) = first_shape(&s, l);
+    let uid_of = |s: &Session, id: &str| layer(s, l).props.sub("contents").unwrap().find_group(uid).unwrap().get(id).unwrap().uid;
+    for (id, expression) in [("perCorner", "true"), ("topLeftRoundness", "20")] {
+        let u = uid_of(&s, id);
+        s.execute("prop.setExpression", json!({"layer": l, "path": format!("@{u}"), "expression": expression})).unwrap();
+    }
+
+    s.state.selected_props = vec![(LayerId(l), uid)];
+    s.execute("path.convertToBezier", json!({})).unwrap();
+    let (new_uid, now) = first_shape(&s, l);
+    assert_eq!(now, "path");
+    let path = shape_path_of(&s, l, new_uid);
+    let expected = effectcraft_path::from_kurbo(&effectcraft_path::rect_radii([120.0, 80.0], [0.0, 0.0], [20.0, 0.0, 0.0, 0.0])).into_iter().next().unwrap();
+    assert_eq!(path, expected, "the expression-evaluated corner is converted");
+}
+
 /// #2201: a viewer drag on the free-transform box sends one `path.freeTransform` per frame with a
 /// shared merge key; one undo must revert the whole drag, not the last frame.
 #[test]
diff --git a/crates/lottie/src/shapes.rs b/crates/lottie/src/shapes.rs
index 990a0f28b..fc823b775 100644
--- a/crates/lottie/src/shapes.rs
+++ b/crates/lottie/src/shapes.rs
@@ -113,6 +113,9 @@ impl Out<'_, '_> {
     fn f(&self, m: &str) -> f64 {
         self.g.get(m).map(|p| p.value.as_f64()).unwrap_or(0.0)
     }
+    fn flag(&self, m: &str) -> bool {
+        self.g.get(m).map(|p| p.value.as_bool()).unwrap_or(false)
+    }
     fn animated(&self, m: &str) -> bool {
         self.g.get(m).is_some_and(|p| p.is_animated() || p.has_expression())
     }
@@ -232,7 +235,19 @@ pub(crate) fn export_items(ex: &mut Ex, contents: &PropGroup, label: &str) -> Ve
                 dir(&mut o);
                 o.put("s", "size", &anim::arr2);
                 o.put("p", "position", &anim::arr2);
-                o.put("r", "roundness", &anim::num);
+                if o.flag("perCorner") {
+                    let names = ["topLeftRoundness", "topRightRoundness", "bottomRightRoundness", "bottomLeftRoundness"];
+                    let radii = names.map(|m| o.f(m));
+                    // Lottie `rc` has one `r`: four equal static radii export as that value.
+                    if radii.iter().all(|v| (v - radii[0]).abs() < 1e-6) && !names.iter().any(|m| o.animated(m)) && radii[0] >= 0.0 {
+                        o.raw("r", json!(r(radii[0])));
+                    } else {
+                        o.ex.warn(format!("{}: per-corner roundness has no Lottie rectangle equivalent (roundness 0 exported)", o.label));
+                        o.raw("r", json!(0));
+                    }
+                } else {
+                    o.put("r", "roundness", &anim::num);
+                }
             }
             "el" => {
                 dir(&mut o);
@@ -447,6 +462,11 @@ pub(crate) fn import_items(im: &mut Im, ids: &mut Ids, items: &[Json]) -> Vec<Pr
                 set(im, &mut g, "size", j.get("s"), &anim::to_vec2);
                 set(im, &mut g, "position", j.get("p"), &anim::to_vec2);
                 set(im, &mut g, "roundness", j.get("r"), &anim::to_scalar);
+                // Lottie has one roundness: keep the per-corner values in step so ticking the box
+                // on an imported rectangle keeps the shape.
+                for m in ["topLeftRoundness", "topRightRoundness", "bottomRightRoundness", "bottomLeftRoundness"] {
+                    set(im, &mut g, m, j.get("r"), &anim::to_scalar);
+                }
                 g
             }
             "el" => {
diff --git a/crates/lottie/src/tests.rs b/crates/lottie/src/tests.rs
index 203f04c04..24b4690eb 100644
--- a/crates/lottie/src/tests.rs
+++ b/crates/lottie/src/tests.rs
@@ -896,3 +896,39 @@ fn muted_keys_are_omitted_from_the_export() {
     assert!((opacity_at(&p, cid, 1.0) - 150.0).abs() < 1e-6);
     assert!((opacity_at(&q, nc, 1.0) - 150.0).abs() < 1e-6);
 }
+
+#[test]
+fn per_corner_roundness_exports_equal_radii_and_warns_when_mixed() {
+    let shape = |radii: [f64; 4], roundness: f64, per_corner: bool| {
+        let (mut p, cid) = setup();
+        let l = shape_layer(&mut p, cid, move |ids| {
+            let mut g = build::shape_rect(ids, [100.0, 50.0], [0.0, 0.0], roundness);
+            g.prop_mut("perCorner").unwrap().value = Value::Bool(per_corner);
+            for (m, v) in
+                [("topLeftRoundness", radii[0]), ("topRightRoundness", radii[1]), ("bottomRightRoundness", radii[2]), ("bottomLeftRoundness", radii[3])]
+            {
+                g.prop_mut(m).unwrap().value = Value::Scalar(v);
+            }
+            let fill = build::shape_fill(ids, [1.0, 0.0, 0.0, 1.0]);
+            vec![build::shape_group(ids, "Rectangle 1", vec![g, fill])]
+        });
+        push(&mut p, cid, l);
+        (p, cid)
+    };
+    let rc = |json: &Json| -> Json { json["layers"][0]["shapes"][0]["it"].as_array().unwrap().iter().find(|i| i["ty"] == "rc").cloned().unwrap() };
+    // Four equal static radii: `rc.r` carries the value, no warning.
+    let (p, cid) = shape([12.0; 4], 5.0, true);
+    let (_, _, warnings, json) = roundtrip(&p, cid, &ExportOptions::default());
+    assert_eq!(rc(&json)["r"], json!(12.0));
+    assert!(!warnings.iter().any(|w| w.contains("per-corner")), "{warnings:?}");
+    // Mixed radii: not representable, roundness 0 exported with a warning.
+    let (p, cid) = shape([10.0, 20.0, 10.0, 20.0], 5.0, true);
+    let (_, _, warnings, json) = roundtrip(&p, cid, &ExportOptions::default());
+    assert_eq!(rc(&json)["r"], json!(0));
+    assert!(warnings.iter().any(|w| w.contains("per-corner roundness")), "{warnings:?}");
+    // The checkbox off exports the single Roundness and ignores the four values.
+    let (p, cid) = shape([10.0, 20.0, 10.0, 20.0], 5.0, false);
+    let (_, _, warnings, json) = roundtrip(&p, cid, &ExportOptions::default());
+    assert_eq!(rc(&json)["r"]["k"], json!(5.0));
+    assert!(!warnings.iter().any(|w| w.contains("per-corner")), "{warnings:?}");
+}
diff --git a/crates/path/src/lib.rs b/crates/path/src/lib.rs
index 83e2102dc..61fd0e6c3 100644
--- a/crates/path/src/lib.rs
+++ b/crates/path/src/lib.rs
@@ -164,6 +164,52 @@ pub fn rect(size: [f64; 2], pos: [f64; 2], roundness: f64) -> BezPath {
     p
 }
 
+/// Rectangle path centred at `pos` with independent corner radii `[top-left, top-right,
+/// bottom-right, bottom-left]`, clockwise in screen coordinates. Negative and non-finite radii
+/// are 0; radii that would overlap are scaled down as CSS `border-radius` does.
+pub fn rect_radii(size: [f64; 2], pos: [f64; 2], radii: [f64; 4]) -> BezPath {
+    // Start at the end of the top-right arc on the right edge, like `rect`, and walk the corners
+    // clockwise: Trim Paths measures from the first point, so ticking per-corner roundness must
+    // not make a trim jump (#1896).
+    let w = if size[0].is_finite() { size[0].abs() } else { 0.0 };
+    let h = if size[1].is_finite() { size[1].abs() } else { 0.0 };
+    let (x0, y0) = (pos[0] - w / 2.0, pos[1] - h / 2.0);
+    let (x1, y1) = (pos[0] + w / 2.0, pos[1] + h / 2.0);
+    let mut r = radii.map(|v| if v.is_finite() { v.max(0.0) } else { 0.0 });
+    // CSS border-radius: when two radii on an edge overlap, scale every radius by the smallest
+    // edge ratio (a uniform radius then clamps to half the shorter side, as before).
+    let ratio = |a: f64, b: f64, edge: f64| if a + b > edge && a + b > 0.0 { (edge / (a + b)).min(1.0) } else { 1.0 };
+    let f = ratio(r[0], r[1], w).min(ratio(r[3], r[2], w)).min(ratio(r[0], r[3], h)).min(ratio(r[1], r[2], h));
+    if f < 1.0 {
+        for v in &mut r {
+            *v *= f;
+        }
+    }
+    let [tl, tr, br, bl] = r;
+    // Quarter-circle Bezier control distance.
+    const K: f64 = 0.552_284_749_830_793_6;
+    let mut p = BezPath::new();
+    p.move_to((x1, y0 + tr));
+    p.line_to((x1, y1 - br));
+    if br > 0.0 {
+        p.curve_to((x1, y1 - br + K * br), (x1 - br + K * br, y1), (x1 - br, y1));
+    }
+    p.line_to((x0 + bl, y1));
+    if bl > 0.0 {
+        p.curve_to((x0 + bl - K * bl, y1), (x0, y1 - bl + K * bl), (x0, y1 - bl));
+    }
+    p.line_to((x0, y0 + tl));
+    if tl > 0.0 {
+        p.curve_to((x0, y0 + tl - K * tl), (x0 + tl - K * tl, y0), (x0 + tl, y0));
+    }
+    p.line_to((x1 - tr, y0));
+    if tr > 0.0 {
+        p.curve_to((x1 - tr + K * tr, y0), (x1, y0 + tr - K * tr), (x1, y0 + tr));
+    }
+    p.close_path();
+    p
+}
+
 pub fn ellipse(size: [f64; 2], pos: [f64; 2]) -> BezPath {
     to_kurbo(&ShapePath::ellipse(pos, size[0], size[1]))
 }
@@ -419,6 +465,11 @@ mod tests {
         let round = ops::trim(&[rect([400.0, 300.0], [0.0, 0.0], 40.0)], 0.0, 25.0, 0.0);
         let (a, b) = ends(&round[0]);
         assert!(near(a, (200.0, -110.0)) && near(b, (110.0, 150.0)), "{a:?} {b:?}");
+        // Per-corner roundness starts and runs in the same order: ticking the checkbox must not
+        // move a Trim Paths contour.
+        let corners = ops::trim(&[rect_radii([400.0, 300.0], [0.0, 0.0], [40.0; 4])], 0.0, 25.0, 0.0);
+        let (a, b) = ends(&corners[0]);
+        assert!(near(a, (200.0, -110.0)) && near(b, (110.0, 150.0)), "per-corner: {a:?} {b:?}");
         // Start > End: AE draws 30..70 % (plain: from x 80 on the bottom up to y −130 on the left).
         let swapped = ops::trim(&[rect([400.0, 300.0], [0.0, 0.0], 0.0)], 70.0, 30.0, 0.0);
         let (a, b) = ends(&swapped[0]);
@@ -456,6 +507,32 @@ mod tests {
         assert!((area - 200.0).abs() < 1.0, "{area}");
     }
 
+    #[test]
+    fn rect_radii_uniform_matches_a_rounded_rect() {
+        for r in [0.0, 5.0, 25.0, 100.0] {
+            let p = rect_radii([100.0, 50.0], [10.0, 20.0], [r; 4]);
+            let clamped = r.min(25.0);
+            let expect = 100.0 * 50.0 - (4.0 - std::f64::consts::PI) * clamped * clamped;
+            assert!((p.area().abs() - expect).abs() < 1.0, "{r}: {} != {expect}", p.area());
+            assert!((p.area() - rect([100.0, 50.0], [10.0, 20.0], r).area()).abs() < 1e-6);
+        }
+    }
+
+    #[test]
+    fn rect_radii_mixes_corners_and_scales_overlaps() {
+        // Only the top-left and bottom-right corners round.
+        let p = rect_radii([100.0, 50.0], [0.0, 0.0], [10.0, 0.0, 20.0, 0.0]);
+        let expect = 100.0 * 50.0 - (1.0 - std::f64::consts::PI / 4.0) * (10.0 * 10.0 + 20.0 * 20.0);
+        assert!((p.area().abs() - expect).abs() < 1.0, "{}", p.area());
+        // Radii wider than the top edge scale down together, like CSS border-radius.
+        let p = rect_radii([50.0, 100.0], [0.0, 0.0], [40.0, 40.0, 0.0, 0.0]);
+        let scaled = rect_radii([50.0, 100.0], [0.0, 0.0], [25.0, 25.0, 0.0, 0.0]);
+        assert!((p.area() - scaled.area()).abs() < 1e-9);
+        // Negative and non-finite radii are square corners.
+        let p = rect_radii([50.0, 50.0], [0.0, 0.0], [-5.0, f64::NAN, f64::INFINITY, 0.0]);
+        assert!((p.area().abs() - 2500.0).abs() < 1e-9);
+    }
+
     #[test]
     fn stroke_has_area() {
         let r = rect([40.0, 40.0], [50.0, 50.0], 0.0);
diff --git a/crates/project/src/build.rs b/crates/project/src/build.rs
index 3ff61ba7d..1aa8d7c90 100644
--- a/crates/project/src/build.rs
+++ b/crates/project/src/build.rs
@@ -385,11 +385,18 @@ pub fn shape_group(ids: &mut Ids, name: &str, items: Vec<PropGroup>) -> PropGrou
 }
 
 pub fn shape_rect(ids: &mut Ids, size: [f64; 2], position: [f64; 2], roundness: f64) -> PropGroup {
+    // Per-corner radii start from the uniform Roundness, so ticking the box keeps the shape.
+    let r = if roundness.is_finite() { roundness.max(0.0) } else { 0.0 };
     indexed(ids.group("rect", "Rectangle Path 1"))
         .with(ids.prop("direction", "Path Direction", Value::Enum(0)).with_ui(ParamUi::Hidden))
         .with(ids.prop("size", "Size", Value::Vec2(size)).with_ui(ParamUi::Pixels))
         .with(ids.prop("position", "Position", Value::Vec2(position)).with_ui(ParamUi::Point))
         .with(ids.prop("roundness", "Roundness", Value::Scalar(roundness)).with_ui(ParamUi::Pixels))
+        .with(ids.prop("perCorner", "Per-Corner Roundness", Value::Bool(false)).with_ui(ParamUi::Checkbox))
+        .with(ids.prop("topLeftRoundness", "Top Left Roundness", Value::Scalar(r)).with_ui(ParamUi::Pixels))
+        .with(ids.prop("topRightRoundness", "Top Right Roundness", Value::Scalar(r)).with_ui(ParamUi::Pixels))
+        .with(ids.prop("bottomRightRoundness", "Bottom Right Roundness", Value::Scalar(r)).with_ui(ParamUi::Pixels))
+        .with(ids.prop("bottomLeftRoundness", "Bottom Left Roundness", Value::Scalar(r)).with_ui(ParamUi::Pixels))
 }
 
 pub fn shape_ellipse(ids: &mut Ids, size: [f64; 2], position: [f64; 2]) -> PropGroup {
diff --git a/crates/render/src/shapes.rs b/crates/render/src/shapes.rs
index bbc4283ff..2497ea807 100644
--- a/crates/render/src/shapes.rs
+++ b/crates/render/src/shapes.rs
@@ -269,7 +269,20 @@ fn collect_in(ctx: &EvalCtx, layer: &Layer, contents: &PropGroup, arena: &mut Ve
             "rect" => {
                 let size = ctx.v2(layer, g, "size", [100.0; 2]);
                 let pos = ctx.v2(layer, g, "position", [0.0; 2]);
-                let p = effectcraft_path::rect(size, pos, ctx.f(layer, g, "roundness", 0.0));
+                let p = if ctx.b(layer, g, "perCorner") {
+                    effectcraft_path::rect_radii(
+                        size,
+                        pos,
+                        [
+                            ctx.f(layer, g, "topLeftRoundness", 0.0),
+                            ctx.f(layer, g, "topRightRoundness", 0.0),
+                            ctx.f(layer, g, "bottomRightRoundness", 0.0),
+                            ctx.f(layer, g, "bottomLeftRoundness", 0.0),
+                        ],
+                    )
+                } else {
+                    effectcraft_path::rect(size, pos, ctx.f(layer, g, "roundness", 0.0))
+                };
                 push_shape(ctx, layer, g, p, arena, &mut live);
             }
             "ellipse" => {
diff --git a/crates/render/src/shapes/tests.rs b/crates/render/src/shapes/tests.rs
index e0c9086a7..ba7028a25 100644
--- a/crates/render/src/shapes/tests.rs
+++ b/crates/render/src/shapes/tests.rs
@@ -715,3 +715,33 @@ fn miter_corner_still_fits_its_buffer() {
     let b = shape_buf(&p, cid);
     assert!(b.img.height as f64 >= 50.0 + 20.0 * 4.0 * 0.5, "{}", b.img.height);
 }
+
+#[test]
+fn rect_per_corner_roundness_rounds_the_named_corners() {
+    let render = |per_corner: bool, radii: [f64; 4], roundness: f64| {
+        let (p, cid) = shape_comp_sized(200, 100, move |ids| {
+            let mut g = build::shape_rect(ids, [100.0, 100.0], [0.0, 0.0], roundness);
+            g.prop_mut("perCorner").unwrap().value = Value::Bool(per_corner);
+            for (m, v) in
+                [("topLeftRoundness", radii[0]), ("topRightRoundness", radii[1]), ("bottomRightRoundness", radii[2]), ("bottomLeftRoundness", radii[3])]
+            {
+                g.prop_mut(m).unwrap().value = Value::Scalar(v);
+            }
+            vec![g, build::shape_fill(ids, RED)]
+        });
+        frame(&p, cid)
+    };
+    // Only the top-left corner rounds: its corner pixels fade, the other three stay filled.
+    let img = render(true, [30.0, 0.0, 0.0, 0.0], 0.0);
+    assert!(alpha(&img, 52, 2) < 0.1, "top-left rounds: {}", alpha(&img, 52, 2));
+    for (x, y) in [(148, 2), (148, 98), (52, 98)] {
+        assert!(alpha(&img, x, y) > 0.9, "({x},{y}) stays square: {}", alpha(&img, x, y));
+    }
+    // The checkbox off ignores the four values (the single Roundness still rules).
+    let off = render(false, [30.0; 4], 0.0);
+    assert!((coverage(&off) - 100.0 * 100.0).abs() < 20.0, "{}", coverage(&off));
+    // Four equal per-corner radii render like the same Roundness.
+    let per = render(true, [25.0; 4], 0.0);
+    let uni = render(false, [0.0; 4], 25.0);
+    assert!((coverage(&per) - coverage(&uni)).abs() < 5.0, "{} vs {}", coverage(&per), coverage(&uni));
+}
diff --git a/crates/ui-egui/src/panels/timeline/tests.rs b/crates/ui-egui/src/panels/timeline/tests.rs
index 12259abf7..9a5c89f7d 100644
--- a/crates/ui-egui/src/panels/timeline/tests.rs
+++ b/crates/ui-egui/src/panels/timeline/tests.rs
@@ -195,6 +195,11 @@ fn shape_group_inner_contents_is_elided() {
             "        Size",
             "        Position",
             "        Roundness",
+            "        Per-Corner Roundness",
+            "        Top Left Roundness",
+            "        Top Right Roundness",
+            "        Bottom Right Roundness",
+            "        Bottom Left Roundness",
             "      >Fill 1",
             "        Composite",
             "        Fill Rule",
diff --git a/crates/ui-egui/tests/it/ui_timeline_shapes.rs b/crates/ui-egui/tests/it/ui_timeline_shapes.rs
index 73686ee99..cd56db825 100644
--- a/crates/ui-egui/tests/it/ui_timeline_shapes.rs
+++ b/crates/ui-egui/tests/it/ui_timeline_shapes.rs
@@ -340,6 +340,11 @@ fn timeline_colour_eyedropper_samples_the_comp() {
     let fill = fill.expect("a fill colour");
     fn groups(g: &effectcraft_engine::project::PropGroup, out: &mut Vec<u64>) {
         for c in g.groups() {
+            // The rectangle's path rows would push Fill below the rows the Timeline fits; the
+            // eyedropper only needs Fill, so leave that group collapsed.
+            if c.name == "Rectangle Path 1" {
+                continue;
+            }
             out.push(c.uid);
             groups(c, out);
         }

From d249f255ae7852e23f285a473640b9720cf1819e Mon Sep 17 00:00:00 2001
From: Camille Moine <ki2pixel@gmail.com>
Date: Mon, 19 Oct 2026 21:08:54 +0200
Subject: [PATCH 08/13] Shapes: export per-corner `rc.r` as a Lottie property

The equal-radii and zero fallback branches wrote a bare number where the
uniform branch (and every other Value field) writes `{a, k}`; external
players may reject that form even though our importer reads it. Write
`{"a": 0, "k": value}` in both branches and update the export assertions.
---
 crates/lottie/src/shapes.rs | 5 +++--
 crates/lottie/src/tests.rs  | 4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/crates/lottie/src/shapes.rs b/crates/lottie/src/shapes.rs
index fc823b775..5b9d29970 100644
--- a/crates/lottie/src/shapes.rs
+++ b/crates/lottie/src/shapes.rs
@@ -239,11 +239,12 @@ pub(crate) fn export_items(ex: &mut Ex, contents: &PropGroup, label: &str) -> Ve
                     let names = ["topLeftRoundness", "topRightRoundness", "bottomRightRoundness", "bottomLeftRoundness"];
                     let radii = names.map(|m| o.f(m));
                     // Lottie `rc` has one `r`: four equal static radii export as that value.
+                    // `r` is a property (`{a, k}`) like the uniform branch writes, not a bare number.
                     if radii.iter().all(|v| (v - radii[0]).abs() < 1e-6) && !names.iter().any(|m| o.animated(m)) && radii[0] >= 0.0 {
-                        o.raw("r", json!(r(radii[0])));
+                        o.raw("r", json!({"a": 0, "k": r(radii[0])}));
                     } else {
                         o.ex.warn(format!("{}: per-corner roundness has no Lottie rectangle equivalent (roundness 0 exported)", o.label));
-                        o.raw("r", json!(0));
+                        o.raw("r", json!({"a": 0, "k": 0}));
                     }
                 } else {
                     o.put("r", "roundness", &anim::num);
diff --git a/crates/lottie/src/tests.rs b/crates/lottie/src/tests.rs
index 24b4690eb..83c81e242 100644
--- a/crates/lottie/src/tests.rs
+++ b/crates/lottie/src/tests.rs
@@ -919,12 +919,12 @@ fn per_corner_roundness_exports_equal_radii_and_warns_when_mixed() {
     // Four equal static radii: `rc.r` carries the value, no warning.
     let (p, cid) = shape([12.0; 4], 5.0, true);
     let (_, _, warnings, json) = roundtrip(&p, cid, &ExportOptions::default());
-    assert_eq!(rc(&json)["r"], json!(12.0));
+    assert_eq!(rc(&json)["r"], json!({"a": 0, "k": 12.0}));
     assert!(!warnings.iter().any(|w| w.contains("per-corner")), "{warnings:?}");
     // Mixed radii: not representable, roundness 0 exported with a warning.
     let (p, cid) = shape([10.0, 20.0, 10.0, 20.0], 5.0, true);
     let (_, _, warnings, json) = roundtrip(&p, cid, &ExportOptions::default());
-    assert_eq!(rc(&json)["r"], json!(0));
+    assert_eq!(rc(&json)["r"], json!({"a": 0, "k": 0}));
     assert!(warnings.iter().any(|w| w.contains("per-corner roundness")), "{warnings:?}");
     // The checkbox off exports the single Roundness and ignores the four values.
     let (p, cid) = shape([10.0, 20.0, 10.0, 20.0], 5.0, false);

From 1c1faaa758793129571d3aaa4b244c1e0f85d70b Mon Sep 17 00:00:00 2001
From: bflatastic <bombayapirat@gmail.com>
Date: Fri, 30 Oct 2026 07:26:44 +0700
Subject: [PATCH 09/13] Timeline: Shift-click adds effects and other groups to
 the selection (#2552)

Clicking an effect, Layer Style, mask or shape item row in the Timeline
always replaced the selection, so one animation preset couldn't hold
several effects and styles. Shift or Cmd/Ctrl now adds the group to the
selection, or takes a selected one out, as property rows and Effect
Controls headers already do.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 crates/ui-egui/src/panels/timeline.rs         | 10 ++++-
 crates/ui-egui/tests/it/ui_timeline_shapes.rs | 39 +++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/crates/ui-egui/src/panels/timeline.rs b/crates/ui-egui/src/panels/timeline.rs
index e8e771d21..8971ba5c5 100644
--- a/crates/ui-egui/src/panels/timeline.rs
+++ b/crates/ui-egui/src/panels/timeline.rs
@@ -3591,7 +3591,15 @@ fn group_row_click(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: &mut Rw, rc:
     }
     app.auto.add(&format!("timeline.group.{uid}.name"), gr_rect, name);
     if gr.clicked() && uid & (WAVE_BIT | GEOM_BIT) == 0 {
-        actions.push(("prop.select".into(), json!({"layer": layer.id.0, "prop": uid, "selectKeys": false})));
+        // Shift or Cmd/Ctrl adds the group to the selection, or takes a selected one out, as
+        // property rows and Effect Controls headers do (#2552: several effects and styles for
+        // one animation preset).
+        let add = ui.input(|i| i.modifiers.shift || i.modifiers.command);
+        if add && app.session.state.selected_props.contains(&(layer.id, *uid)) {
+            actions.push(("prop.deselect".into(), json!({"layer": layer.id.0, "prop": uid})));
+        } else {
+            actions.push(("prop.select".into(), json!({"layer": layer.id.0, "prop": uid, "selectKeys": false, "add": add})));
+        }
     }
     if gr.double_clicked() {
         if fx.is_some() {
diff --git a/crates/ui-egui/tests/it/ui_timeline_shapes.rs b/crates/ui-egui/tests/it/ui_timeline_shapes.rs
index 73686ee99..c9b2245f8 100644
--- a/crates/ui-egui/tests/it/ui_timeline_shapes.rs
+++ b/crates/ui-egui/tests/it/ui_timeline_shapes.rs
@@ -448,3 +448,42 @@ fn effects_drag_to_a_new_place_in_the_timeline() {
     h.state_mut().session.execute("edit.undo", json!({})).unwrap();
     assert_eq!(names(&h), ["Tint", "Gaussian Blur", "Invert"], "one undo step per drop");
 }
+
+/// #2552: Shift-clicking effect rows in the Timeline adds them to the selection (and a second
+/// Shift-click takes one out), so one animation preset can hold several effects.
+#[test]
+fn shift_click_selects_several_effects_for_a_preset() {
+    let mut s = session();
+    let l = s.execute("layer.newSolid", json!({"name": "Plate", "color": "#406080"})).unwrap()["layer"].as_u64().unwrap();
+    for fx in ["Gaussian Blur", "Invert"] {
+        s.execute("effect.apply", json!({"layers": [l], "effect": fx})).unwrap();
+    }
+    let effects = s.active_comp().unwrap().layer(LayerId(l)).unwrap().props.sub("effects").unwrap().clone();
+    let uids: Vec<u64> = effects.groups().map(|g| g.uid).collect();
+    let mut h = harness(s);
+    h.state_mut().ui.timeline.open_groups.insert(effects.uid);
+    open_layer(&mut h, l);
+    let shift_click = |h: &mut Harness<'_, EffectcraftApp>, uid: u64| {
+        let p = center(h, &format!("timeline.group.{uid}.name"));
+        h.input_mut().events.push(Event::ModifiersChanged(Modifiers::SHIFT));
+        h.input_mut().events.push(Event::PointerMoved(p));
+        h.step();
+        for pressed in [true, false] {
+            h.input_mut().events.push(Event::PointerButton { pos: p, button: PointerButton::Primary, pressed, modifiers: Modifiers::SHIFT });
+            h.step();
+        }
+        h.input_mut().events.push(Event::ModifiersChanged(Modifiers::NONE));
+        h.run_steps(2);
+    };
+    let selected = |h: &Harness<'_, EffectcraftApp>| h.state().session.state.selected_props.iter().map(|(_, u)| *u).collect::<Vec<_>>();
+    click(&mut h, &format!("timeline.group.{}.name", uids[0]));
+    assert_eq!(selected(&h), [uids[0]]);
+    shift_click(&mut h, uids[1]);
+    assert_eq!(selected(&h), [uids[0], uids[1]], "Shift adds the second effect");
+    let path = std::env::temp_dir().join(format!("ec-2552-{}.ffx", std::process::id()));
+    let r = h.state_mut().session.execute("anim.savePreset", json!({"path": path.to_string_lossy()})).unwrap();
+    assert_eq!(r["effects"], 2, "{r}");
+    let _ = std::fs::remove_file(&path);
+    shift_click(&mut h, uids[1]);
+    assert_eq!(selected(&h), [uids[0]], "a second Shift-click takes it out");
+}

From 5bb66bad745fcec1f68e0f6a28a7697ba596aec1 Mon Sep 17 00:00:00 2001
From: bflatastic <bombayapirat@gmail.com>
Date: Fri, 30 Oct 2026 07:37:19 +0700
Subject: [PATCH 10/13] ScriptUI: a docked panel gets its dock's size and
 onResize (#2585)

A docked ScriptUI panel only ever saw its preferredSize: the host drew
it in a scroll area at max(dock, preferred) and the script's window never
learned the dock. scriptui.resize now gives a window a size: the script's
window takes it, lays itself out again and runs onResizing / onResize.
The dock host sends it whenever the panel's dock size changes, so
window.size is the dock's, as in After Effects.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 crates/engine/src/cmd/scripts.rs           |  9 ++++++
 crates/engine/src/scriptui.rs              | 11 ++++++++
 crates/script/src/scriptui.js              | 12 ++++++++
 crates/ui-egui/src/panels/scriptui_view.rs | 11 ++++++++
 crates/ui-egui/tests/it/ui_scriptui.rs     | 32 ++++++++++++++++++++++
 5 files changed, 75 insertions(+)

diff --git a/crates/engine/src/cmd/scripts.rs b/crates/engine/src/cmd/scripts.rs
index a523770e3..a92d484a7 100644
--- a/crates/engine/src/cmd/scripts.rs
+++ b/crates/engine/src/cmd/scripts.rs
@@ -467,6 +467,15 @@ pub fn specs() -> Vec<CommandSpec> {
             always,
             scriptui::mouse
         ),
+        cmd!(
+            "scriptui.resize",
+            "Resize Script Window",
+            [],
+            None,
+            "{window?, size: [width, height] (pixels)} → the window takes the size, lays itself out again and its onResizing / onResize run (a docked ScriptUI panel gets its dock's size)",
+            always,
+            scriptui::resize
+        ),
         cmd!(
             "scriptui.close",
             "Close Script Window",
diff --git a/crates/engine/src/scriptui.rs b/crates/engine/src/scriptui.rs
index af89932fa..d8f9f1d1e 100644
--- a/crates/engine/src/scriptui.rs
+++ b/crates/engine/src/scriptui.rs
@@ -765,6 +765,17 @@ pub(crate) fn mouse(s: &mut Session, p: &Value) -> Result<Value> {
     dispatch(s, ScriptUiEvent { window, widget, kind: (*ty).to_string(), value })
 }
 
+/// `scriptui.resize`: the host gave the window a new size (a docked panel's dock, #2585): the
+/// script's window takes it, lays itself out again and gets `onResizing` / `onResize`.
+pub(crate) fn resize(s: &mut Session, p: &Value) -> Result<Value> {
+    let c = "scriptui.resize";
+    let window = window_p(s, p, c)?;
+    let size = p.get("size").and_then(Value::as_array).ok_or_else(|| crate::commands::bad(c, "missing `size` [width, height]"))?;
+    let side = |i: usize| size.get(i).and_then(Value::as_f64).filter(|v| v.is_finite()).map(|v| v.round().clamp(1.0, 16384.0));
+    let (Some(w), Some(h)) = (side(0), side(1)) else { return Err(crate::commands::bad(c, "`size` must be [width, height] in pixels")) };
+    dispatch(s, ScriptUiEvent { window, widget: 0, kind: "resize".into(), value: json!([w, h]) })
+}
+
 /// `scriptui.close`: close a window (a dialog's `show()` returns `result`, default 2 = Cancel).
 pub(crate) fn close(s: &mut Session, p: &Value) -> Result<Value> {
     let window = window_p(s, p, "scriptui.close")?;
diff --git a/crates/script/src/scriptui.js b/crates/script/src/scriptui.js
index 178bd8be1..ddfbc1f3e 100644
--- a/crates/script/src/scriptui.js
+++ b/crates/script/src/scriptui.js
@@ -912,6 +912,18 @@ function __uiDispatch(winId, id, kind, valueJson) {
     w.close(v === null ? 2 : v);
     return;
   }
+  // The host gave the window a new size (a docked panel's dock): take it, lay out, tell the script.
+  if (kind === "resize") {
+    var nw = Number(v && v[0]), nh = Number(v && v[1]);
+    var b = w.__ub || w.__lb;
+    if (nw > 0 && nh > 0 && (b[2] - b[0] !== nw || b[3] - b[1] !== nh)) {
+      w.__ub = [b[0], b[1], b[0] + nw, b[1] + nh];
+      __uiLayout(w);
+      w.__fire("onResizing");
+      w.__fire("onResize");
+    }
+    return;
+  }
   var c = __uiFind(w, id);
   if (!c || c.enabled === false) return;
   var radio = function () {
diff --git a/crates/ui-egui/src/panels/scriptui_view.rs b/crates/ui-egui/src/panels/scriptui_view.rs
index 14460ed28..753b2884e 100644
--- a/crates/ui-egui/src/panels/scriptui_view.rs
+++ b/crates/ui-egui/src/panels/scriptui_view.rs
@@ -26,6 +26,8 @@ enum Act {
     Close(u32),
     /// A mouse event (`scriptui.mouse` parameters without window and widget).
     Mouse(u32, u32, Value),
+    /// A docked panel's new size (`scriptui.resize`).
+    Resize(u32, [f32; 2]),
 }
 
 fn rect_of(origin: egui::Pos2, b: [f64; 4]) -> Rect {
@@ -500,6 +502,7 @@ fn perform(app: &mut EffectcraftApp, ctx: &egui::Context, acts: Vec<Act>) {
             Act::Set(w, id, v) => ("scriptui.set", json!({"window": w, "widget": id, "value": v})),
             Act::Changing(w, id, v) => ("scriptui.set", json!({"window": w, "widget": id, "value": v, "changing": true})),
             Act::Close(w) => ("scriptui.close", json!({"window": w})),
+            Act::Resize(w, [x, y]) => ("scriptui.resize", json!({"window": w, "size": [x, y]})),
             Act::Mouse(w, id, mut v) => {
                 if let Some(o) = v.as_object_mut() {
                     o.insert("window".into(), json!(w));
@@ -582,6 +585,14 @@ pub fn panel(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect, id: u32) {
     // A modal script dialog blocks the panels too.
     let modal = app.session.script_ui.windows.iter().any(|w| w.modal);
     let mut acts = vec![];
+    // The script learns its dock's size when it changes (#2585), as After Effects tells a
+    // docked panel: its window takes the size and onResize runs.
+    let dock = [rect.width().round(), rect.height().round()];
+    let told = egui::Id::unique(("scriptui-dock-size", id));
+    if ui.data(|d| d.get_temp::<[f32; 2]>(told)) != Some(dock) && dock[0] >= 1.0 && dock[1] >= 1.0 {
+        ui.data_mut(|d| d.insert_temp(told, dock));
+        acts.push(Act::Resize(id, dock));
+    }
     let content = rect;
     egui::ScrollArea::both().id_salt(("scriptui-panel", id)).max_width(content.width()).max_height(content.height()).show(ui, |ui| {
         let (r, _) = ui.allocate_exact_size(vec2(w.root.bounds[2] as f32, w.root.bounds[3] as f32), Sense::hover());
diff --git a/crates/ui-egui/tests/it/ui_scriptui.rs b/crates/ui-egui/tests/it/ui_scriptui.rs
index 2669a2631..8a248155b 100644
--- a/crates/ui-egui/tests/it/ui_scriptui.rs
+++ b/crates/ui-egui/tests/it/ui_scriptui.rs
@@ -305,6 +305,38 @@ fn a_drag_keeps_its_control_past_the_window_edge() {
     h.state_mut().session.execute("scriptui.close", json!({})).unwrap();
 }
 
+/// #2585: a window the host resizes takes the size, lays out again and runs onResize; a docked
+/// ScriptUI panel gets its dock's size that way.
+#[test]
+fn script_windows_learn_the_size_they_are_given() {
+    let mut h = harness();
+    let code = r#"
+      var w = new Window("palette", "Sized");
+      var log = w.add("statictext", undefined, "", { name: "log" });
+      log.preferredSize = [200, 20];
+      w.onResize = function () { log.text = "resized " + w.size.width + "x" + w.size.height; };
+      w.show();
+    "#;
+    let r = h.state_mut().session.execute("script.run", json!({"code": code, "name": "sized.jsx"})).unwrap();
+    assert_eq!(r["ok"], true, "{r}");
+    h.run_steps(2);
+    h.state_mut().session.execute("scriptui.resize", json!({"window": "Sized", "size": [300, 180]})).unwrap();
+    let win = h.state().session.script_ui.windows[0].clone();
+    assert_eq!(win.root.lookup(&json!("log")).unwrap().text, "resized 300x180");
+    let list = h.state_mut().session.execute("scriptui.list", json!({})).unwrap();
+    assert_eq!(list[0]["size"], json!([300.0, 180.0]), "{list}");
+    assert!(h.state_mut().session.execute("scriptui.resize", json!({"window": "Sized", "size": ["wide", 1]})).is_err());
+    h.state_mut().session.execute("scriptui.close", json!({})).unwrap();
+    // A docked panel: its window is its dock's size, not its preferred size.
+    h.state_mut().session.execute("window.scriptPanel", json!({"name": "Layer Tools.jsx"})).unwrap();
+    h.run_steps(4);
+    let panel = h.state().session.script_ui.windows.iter().find(|w| w.script == "Layer Tools.jsx").unwrap().clone();
+    let dock = rect(&h, &format!("scriptui.{}", panel.id));
+    assert_eq!([panel.root.bounds[2].round(), panel.root.bounds[3].round()], [dock.width().round() as f64, dock.height().round() as f64]);
+    h.state_mut().close_panel(PanelKind::ScriptPanel(panel.id));
+    h.run_steps(2);
+}
+
 fn click_at(h: &mut Harness<'_, EffectcraftApp>, c: egui::Pos2) {
     h.input_mut().events.push(Event::PointerMoved(c));
     h.run_steps(1);

From df21aff0d80ab36583cb3cae3a5cf447902cb95d Mon Sep 17 00:00:00 2001
From: bflatastic <bombayapirat@gmail.com>
Date: Fri, 30 Oct 2026 07:46:50 +0700
Subject: [PATCH 11/13] Docs: ROADMAP progress log and ScriptUI parity for 30
 October's features

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 ROADMAP.md               | 11 ++++++++++-
 docs/scripting-parity.md |  2 +-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/ROADMAP.md b/ROADMAP.md
index f3e6750ed..740ec6010 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -2,7 +2,7 @@
 
 **Stage: alpha** · next: beta, ~30 points of "ready for real work" and ~350–620 h away
 
-> **Last reviewed:** 2026-10-22 · **Last updated:** 2026-10-30 · **Change:** minor (localization: 303 more panel/dialog rows in Japanese and the Chinese catalogs; recounted after #1774: Japanese 27% → 46%, Simplified Chinese 29% → 46%, Traditional Chinese 29% → 38%, overall 18% → 24%) · **Target:** Adobe After Effects 2026 (26.5.0.89)
+> **Last reviewed:** 2026-10-22 · **Last updated:** 2026-10-30 · **Change:** minor (features of 30 October in the progress log: text Line Join, Timeline drag-reorder and multi-select of effects, viewer edge pan, ScriptUI drag capture and dock size; previously: localization recount after #1774) · **Target:** Adobe After Effects 2026 (26.5.0.89)
 
 EffectCraft aims to do what After Effects does, with the same panels, menus and behaviour, written
 from scratch in Rust. This page is the one-page summary; the evidence is in
@@ -117,6 +117,14 @@ Come tell us what matters most to you on [Discord](https://discord.gg/artcraft).
 
 ## Progress log
 
+- 2026-10-30: Text strokes take a Line Join (Miter, Round or Bevel) in the Character panel,
+  Miter for new text as in After Effects (#2077). In the Timeline, effects, masks and shape items
+  drag to a new place in their stack (#2210) and Shift-click adds them to the selection, so one
+  animation preset can hold several (#2552). The Composition panel pans while a mask vertex is
+  held at its edge (#999). Effect buffers that pad a small layer stay within a memory budget
+  (#2261); an MP4 lasts as long as its edit list shows (#2592); the Render Queue's times tick
+  between frames (#2593). ScriptUI drags keep their control past the window edge with
+  `MouseEvent.buttons` (#2584), and docked panels get their dock's size and `onResize` (#2585).
 - 2026-10-28: A shape layer's Rectangle and Ellipse Size get the Constrain Proportions chain
   that Scale has, so a circle stays a circle while its size is typed, scrubbed or keyed; it
   starts off, so existing shapes behave as before (#2489).
@@ -169,6 +177,7 @@ Come tell us what matters most to you on [Discord](https://discord.gg/artcraft).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-30 | minor | Progress log: text Line Join, Timeline drag-reorder and Shift multi-select of effects, viewer edge pan, effect padding budget, MP4 edit-list duration, Render Queue clock, ScriptUI drag capture and docked-panel size |
 | 2026-10-22 | minor | Localization: 300 more panel/dialog rows in Japanese and the Chinese catalogs, plus the review's three missing rows (Basic, Advanced, Play/Stop) — panel tabs, form and dialog labels, context menus, tracker/graph/text-panel controls, File-panel footers, credits; language shares recounted after #1774 (Japanese 27% → 46% with 297 effect names, Simplified Chinese 29% → 46% with 307 effect names, Traditional Chinese 29% → 38%, overall 18% → 24%) |
 | 2026-10-12 | minor | Open-issue count (134 to 216), crash list and localization share (12% to 18%) updated to match docs/gaps.md |
 | 2026-10-12 | patch | Roto Brush span validation after trimming; command regressions for both layer edges |
diff --git a/docs/scripting-parity.md b/docs/scripting-parity.md
index 8d2934518..96e298ece 100644
--- a/docs/scripting-parity.md
+++ b/docs/scripting-parity.md
@@ -20,7 +20,7 @@ our own scripts; no real-world script library has been run against both apps.
 | Expression performance | Cached, multi-frame | Per-thread boa contexts | unknown | No benchmark |
 | Scripting object model | `app`, `Project`, items, layers, properties, keys, eases, render queue, `TextDocument`, `Shape`, markers, `File`/`Folder`, `Socket`, `app.settings` | Same classes, edits run through undoable engine commands; match names table; layers, groups and properties are callable (`layer("Effects")(1)` is `.property(...)`) | good | `crates/script` tests (≈ 10 test files) |
 | `$.evalFile`, `BridgeTalk` | Evaluate another script file; identify the host application and message other Adobe applications | `$.evalFile` evaluates a file relative to the calling file (nested at most 32 deep, under the scripts' file gate) and returns its last value; `BridgeTalk` names the host honestly (`appName` `effectcraft`, its version); messaging other applications throws "not supported" | partial | `tests_evalfile.rs` (#760); no inter-application messaging |
-| ScriptUI | Dialogs, palettes, dockable panels, resource strings, `onDraw` / ScriptUIGraphics, mouse events | Same, dockable panels reopen at launch | good | `ui_scriptui`, `tests_ui*` |
+| ScriptUI | Dialogs, palettes, dockable panels, resource strings, `onDraw` / ScriptUIGraphics, mouse events | Same, dockable panels reopen at launch; a docked panel gets its dock's size and `onResize` (`scriptui.resize`, #2585); a drag keeps reaching the control it started on past the window edge, and `MouseEvent.buttons` reports the held buttons (#2584) | good | `ui_scriptui`, `tests_ui*` |
 | `app.scheduleTask` / `cancelTask` | One-shot and repeating tasks (polling, panel refresh) until `cancelTask` | Same: repeating tasks run every `delay` ms (at least 50 ms, at most 64 pending per script) until `cancelTask`, until they throw (reported once, then cancelled), or until their owner goes: a script's last window closing, or the project closing for scripts without windows (a Startup script's tasks go on until EffectCraft quits); frontends tick them every frame, agents with `script.runTasks` | good | `tests_tasks.rs` (#773); one-shot tasks of a script file still run right after it, not after their delay |
 | Scripts menu, ScriptUI Panels folder | yes | yes; a subfolder (one level) of either folder is a submenu named after it | same | [plugins.md](plugins.md) |
 | Startup / Shutdown folders | yes | `Scripts/Startup` runs at launch and `Scripts/Shutdown` runs as the desktop app quits, after the project is closed, each in alphabetical order | partial | `crates/script/src/tests/startup.rs`; each script has its own global scope, so a Startup script's variables and functions are not available to later scripts ([plugins.md](plugins.md)) |

From 1158022585666a11d046351cc5ca448509d83c72 Mon Sep 17 00:00:00 2001
From: bflatastic <bombayapirat@gmail.com>
Date: Fri, 30 Oct 2026 07:53:12 +0700
Subject: [PATCH 12/13] Settings: a dragged UI Scale applies on release (#2582)

Dragging an integer setting applied every step, so UI Scale resized the
interface under the pointer mid-drag. A dragged value now shows in its
field and applies when the button is released (a typed one already
waited for Enter).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 crates/ui-egui/src/panels/settings.rs | 13 ++++++++----
 crates/ui-egui/tests/it/ui_panels.rs  | 30 +++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/crates/ui-egui/src/panels/settings.rs b/crates/ui-egui/src/panels/settings.rs
index f4dd89bfc..562a90132 100644
--- a/crates/ui-egui/src/panels/settings.rs
+++ b/crates/ui-egui/src/panels/settings.rs
@@ -117,15 +117,20 @@ fn page_ui(app: &mut EffectcraftApp, ui: &mut egui::Ui, page: &Page, cur: &Value
                             ui.add_sized(vec2(label_w, 18.0), egui::Label::new(format!("{}:", tr(label))).truncate());
                             let r = match kind {
                                 Kind::Int(lo, hi, unit) => {
-                                    let mut x = v.as_i64().unwrap_or(0);
-                                    // A typed number applies once entered: typing 85 into UI Scale
-                                    // doesn't resize the interface to 75 % at its first digit.
+                                    // A dragged value applies on release, and a typed one once
+                                    // entered: UI Scale doesn't resize the interface under the
+                                    // pointer mid-drag (#2582) or at a typed number's first digit.
+                                    let held = egui::Id::unique(("settings-drag", key));
+                                    let mut x = ui.data(|d| d.get_temp::<i64>(held)).unwrap_or_else(|| v.as_i64().unwrap_or(0));
                                     let drag = egui::DragValue::new(&mut x).range(lo..=hi).speed(0.25).update_while_editing(false);
                                     let r = ui.add(crate::widgets::drag_value(drag));
                                     if !unit.is_empty() {
                                         ui.label(RichText::new(tr(unit)).color(t.text_dim));
                                     }
-                                    if r.changed() {
+                                    if r.dragged() {
+                                        ui.data_mut(|d| d.insert_temp(held, x));
+                                    } else if r.changed() || r.drag_stopped() {
+                                        ui.data_mut(|d| d.remove::<i64>(held));
                                         acts.push(Act::Set(key.into(), json!(x)));
                                     }
                                     r
diff --git a/crates/ui-egui/tests/it/ui_panels.rs b/crates/ui-egui/tests/it/ui_panels.rs
index db9ef7373..6d06c6bf7 100644
--- a/crates/ui-egui/tests/it/ui_panels.rs
+++ b/crates/ui-egui/tests/it/ui_panels.rs
@@ -664,3 +664,33 @@ fn transition_presets_apply_from_effects_and_presets() {
     assert_eq!(fx.name, "Radial Wipe");
     assert_eq!(fx.prop("completion").unwrap().keys.len(), 2);
 }
+
+/// #2582: dragging Settings' UI Scale doesn't resize the interface under the pointer; the value
+/// applies once the button is released.
+#[test]
+fn ui_scale_applies_when_the_drag_ends() {
+    let mut h = harness();
+    open_settings(&mut h);
+    let e = h.state().auto.find("settings.appearance.uiScale").expect("the UI Scale field");
+    let from = pos2(e.rect[0] + e.rect[2] / 2.0, e.rect[1] + e.rect[3] / 2.0);
+    h.input_mut().events.push(Event::PointerMoved(from));
+    h.input_mut().events.push(Event::PointerButton { pos: from, button: egui::PointerButton::Primary, pressed: true, modifiers: Default::default() });
+    h.step();
+    for k in 1..=8 {
+        h.input_mut().events.push(Event::PointerMoved(from + egui::vec2(10.0 * k as f32, 0.0)));
+        h.step();
+        assert_eq!(scale(&h), (100, 1.0), "nothing applies mid-drag");
+    }
+    h.input_mut().events.push(Event::PointerButton {
+        pos: from + egui::vec2(80.0, 0.0),
+        button: egui::PointerButton::Primary,
+        pressed: false,
+        modifiers: Default::default(),
+    });
+    h.run_steps(4);
+    let (pct, zoom) = scale(&h);
+    assert!(pct > 100 && (zoom - pct as f32 / 100.0).abs() < 1e-6, "applied on release: {pct} {zoom}");
+    click(&mut h, "settings.cancel");
+    h.run_steps(2);
+    assert_eq!(scale(&h), (100, 1.0));
+}

From f6222ff5d5c53dc2847c47e61774b10ce4567533 Mon Sep 17 00:00:00 2001
From: erythrofr <20369086+erythrofr@users.noreply.github.com>
Date: Fri, 30 Oct 2026 02:47:31 +0100
Subject: [PATCH 13/13] Tests: document crop/resize regressions

Describe the dimension, pixel-preservation and extreme-input scenarios and
their synthetic-frame helper to address the review's documentation warning.
Test logic and the crop/resize implementation are unchanged.

AI assistance: OpenAI Codex (GPT-6).
---
 crates/export/src/pipeline.rs             | 4 ++++
 crates/export/tests/it/render_settings.rs | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/crates/export/src/pipeline.rs b/crates/export/src/pipeline.rs
index 7b9e4111c..8e8c90561 100644
--- a/crates/export/src/pipeline.rs
+++ b/crates/export/src/pipeline.rs
@@ -1063,6 +1063,7 @@ mod tests {
         }
     }
 
+    /// Regress the locked-aspect example: cropping 1920x1080 must resize to 1280x1440.
     #[test]
     fn crop_resize_applies_margins_once() {
         use effectcraft_project::render_queue::{Crop, OutputModule, Resize};
@@ -1077,6 +1078,7 @@ mod tests {
         assert_eq!(img.data.len(), 1280 * 1440);
     }
 
+    /// Apply output-module geometry to a synthetic frame without rendering or writing files.
     fn run_crop_resize(img: Image, output: &effectcraft_project::render_queue::OutputModule, scale: f64) -> Image {
         use effectcraft_project::render_queue::RenderSettings;
         let project = Project::default();
@@ -1097,6 +1099,7 @@ mod tests {
         Cx::new(&job).crop_resize(img)
     }
 
+    /// Match predicted dimensions across crop, padding, ROI scale, aspect locks and resize qualities.
     #[test]
     fn crop_resize_dimensions_match_the_output_module() {
         use effectcraft_project::render_queue::{Crop, OutputModule, Resize};
@@ -1124,6 +1127,7 @@ mod tests {
         }
     }
 
+    /// Exercise zero/empty inputs, collapsed crops and existing caps on extreme single-axis resizes.
     #[test]
     fn crop_resize_zero_and_extreme_sizes_stay_bounded() {
         use effectcraft_project::render_queue::{Crop, OutputModule, Resize};
diff --git a/crates/export/tests/it/render_settings.rs b/crates/export/tests/it/render_settings.rs
index c2d7dcbfa..0fd6d471b 100644
--- a/crates/export/tests/it/render_settings.rs
+++ b/crates/export/tests/it/render_settings.rs
@@ -174,6 +174,8 @@ fn crop_roi_and_resize() {
     assert_eq!((z.width(), z.height()), (32, 24));
 }
 
+/// Resizing to the cropped frame's own dimensions must preserve every decoded PNG pixel.
+/// Compare against crop-only output for padding and scaled ROIs with both resize qualities.
 #[test]
 fn crop_resize_preserves_pixels_when_the_cropped_size_is_requested() {
     let (p, cid) = project(FrameRate::new(25, 1), |_, _| {});