#986: add Blender scene export for 3D Camera Tracker

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))
+}

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(())
+}

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()

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() {