diff --git a/crates/engine/src/cmd/structure.rs b/crates/engine/src/cmd/structure.rs
index 28a242af..700825f2 100644
--- a/crates/engine/src/cmd/structure.rs
+++ b/crates/engine/src/cmd/structure.rs
@@ -456,16 +456,19 @@ fn outline_stroke(s: &mut Session, p: &Value) -> Result<Value> {
             continue;
         }
         let closed = figcraft_doc::geometry::is_closed(&n);
-        let Some(geom) = (match &n.kind {
-            NodeKind::Text(_) | NodeKind::BooleanOp { .. } => figcraft_render::node_outline(doc, &n).map(|(p, _)| p),
-            _ => figcraft_doc::geometry::stroke_geometry(&n),
+        let Some((area, rule)) = (match &n.kind {
+            NodeKind::Text(_) => figcraft_render::node_outline(doc, &n)
+                .map(|(p, _)| (figcraft_render::draw::stroke_area(&n, &p, closed), figcraft_render::FillRule::Winding)),
+            _ => figcraft_render::stroke_fill(doc, &n),
         }) else {
             continue;
         };
-        let area = figcraft_render::draw::stroke_area(&n, &geom, closed);
         let mut path = (*area).clone();
-        // Union the pieces so the outline is one clean shape.
-        if let Ok(u) = figcraft_pathops::simplify(&path) {
+        // Simplify non-zero strokes into even-odd contours. Inside/outside rings already use
+        // even-odd: interpreting their same-direction contours as non-zero would fill the hole.
+        if rule == figcraft_render::FillRule::Winding
+            && let Ok(u) = figcraft_pathops::simplify(&path)
+        {
             path = u;
         }
         let bb = path.bounding_box();
diff --git a/crates/engine/tests/it/main.rs b/crates/engine/tests/it/main.rs
index a97e3434..34a12847 100644
--- a/crates/engine/tests/it/main.rs
+++ b/crates/engine/tests/it/main.rs
@@ -6,6 +6,8 @@ mod empty_text_box_undo;
 mod library_style_acceptance;
 #[allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
 mod list_indent_response;
+#[allow(clippy::unwrap_used)]
+mod outline_stroke;
 #[allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
 mod scope_reset;
 #[allow(clippy::unwrap_used)]
diff --git a/crates/engine/tests/it/outline_stroke.rs b/crates/engine/tests/it/outline_stroke.rs
new file mode 100644
index 00000000..9efb58c9
--- /dev/null
+++ b/crates/engine/tests/it/outline_stroke.rs
@@ -0,0 +1,172 @@
+//! Outline stroke keeps the renderer's holes and existing property ownership.
+
+use figcraft_doc::{Document, NodeId, NodeKind};
+use figcraft_engine::Session;
+use figcraft_render::{Options, View, render_view};
+use serde_json::{Value, json};
+
+fn run(s: &mut Session, command: &str, params: Value) -> Value {
+    s.execute(command, &params).unwrap()
+}
+
+fn rectangle(s: &mut Session, opacity: f64) -> NodeId {
+    NodeId(
+        run(
+            s,
+            "shape.rectangle",
+            json!({
+                "x": 24, "y": 24, "width": 64, "height": 64,
+                "props": {"fill": "#FF0000", "stroke": "#0000FF", "strokeWeight": 8, "opacity": opacity}
+            }),
+        )["id"]
+            .as_u64()
+            .unwrap(),
+    )
+}
+
+fn pixels(doc: &Document) -> Vec<u8> {
+    render_view(doc, doc.first_page().unwrap(), &View { origin: (0.0, 0.0), scale: 1.0, width: 112, height: 112 }, &Options::default())
+        .unwrap()
+        .data()
+        .to_vec()
+}
+
+fn outlined(s: &mut Session, id: NodeId) -> NodeId {
+    NodeId(run(s, "vector.outlineStroke", json!({"ids": [id]}))["ids"][0].as_u64().unwrap())
+}
+
+fn same_pixels(actual: &[u8], expected: &[u8]) {
+    assert_eq!(actual.len(), expected.len());
+    let differences: Vec<_> = actual.iter().zip(expected).enumerate().filter(|(_, (a, b))| a != b).take(8).collect();
+    assert!(differences.is_empty(), "rendered channels changed (byte, actual/expected): {differences:?}");
+}
+
+#[test]
+fn outline_keeps_rings_through_undo_and_native_reopen() {
+    for vector in [false, true] {
+        let mut s = Session::new();
+        let mut id = rectangle(&mut s, 1.0);
+        if vector {
+            id = NodeId(run(&mut s, "vector.flatten", json!({"ids": [id]}))["id"].as_u64().unwrap());
+        }
+        let before = s.doc().unwrap().clone();
+        let expected = pixels(&before);
+        let depth = s.undo_depth();
+        let group = outlined(&mut s, id);
+        let after = s.doc().unwrap().clone();
+        same_pixels(&pixels(&after), &expected);
+        assert!(after.node(id).unwrap().strokes.is_empty());
+        assert_eq!(s.selection(), vec![group]);
+        assert_eq!(s.undo_depth(), (depth.0 + 1, 0));
+        let (loaded, notes) = figcraft_format::load_bytes(&figcraft_format::save_bytes(&after, None).unwrap()).unwrap();
+        assert!(notes.is_empty(), "{notes:?}");
+        same_pixels(&pixels(&loaded), &expected);
+        assert!(s.undo().unwrap());
+        assert_eq!(serde_json::to_value(s.doc().unwrap()).unwrap(), serde_json::to_value(&before).unwrap());
+        assert!(s.redo().unwrap());
+        assert_eq!(serde_json::to_value(s.doc().unwrap()).unwrap(), serde_json::to_value(&after).unwrap());
+    }
+}
+
+#[test]
+fn stroke_only_keeps_holes_at_each_opacity() {
+    for opacity in [0.0, 0.25, 0.5, 1.0] {
+        let mut s = Session::new();
+        let id = rectangle(&mut s, opacity);
+        run(&mut s, "object.removeFill", json!({"ids": [id]}));
+        let before = pixels(s.doc().unwrap());
+        let vector = outlined(&mut s, id);
+        let doc = s.doc().unwrap();
+        assert!(matches!(doc.node(vector).unwrap().kind, NodeKind::Vector { .. }));
+        assert_eq!(doc.node(vector).unwrap().opacity, opacity as f32);
+        same_pixels(&pixels(doc), &before);
+    }
+}
+
+#[test]
+fn outline_keeps_stroke_holes_and_alignment() {
+    for props in [
+        json!({"strokeAlign": "inside"}),
+        json!({"strokeAlign": "outside"}),
+        json!({"strokeAlign": "center"}),
+        json!({"strokeSides": [2, 4, 8, 16]}),
+        json!({"strokeAlign": "center", "dashes": [8, 4]}),
+    ] {
+        for filled in [false, true] {
+            let mut s = Session::new();
+            let id = rectangle(&mut s, 1.0);
+            run(&mut s, "node.set", json!({"ids": [id], "props": props}));
+            if !filled {
+                run(&mut s, "object.removeFill", json!({"ids": [id]}));
+            }
+            let before = pixels(s.doc().unwrap());
+            outlined(&mut s, id);
+            same_pixels(&pixels(s.doc().unwrap()), &before);
+        }
+    }
+}
+
+#[test]
+fn outlining_an_instance_keeps_its_inherited_opacity_link() {
+    let mut s = Session::new();
+    let component = NodeId(
+        run(
+            &mut s,
+            "frame.create",
+            json!({
+                "width": 64, "height": 64,
+                "props": {"fill": "#FF0000", "stroke": "#0000FF", "strokeWeight": 8, "opacity": 0.5}
+            }),
+        )["id"]
+            .as_u64()
+            .unwrap(),
+    );
+    run(&mut s, "component.create", json!({"ids": [component]}));
+    let instance = NodeId(run(&mut s, "instance.create", json!({"component": component, "x": 200}))["id"].as_u64().unwrap());
+    outlined(&mut s, instance);
+    assert_eq!(s.doc().unwrap().node(instance).unwrap().opacity, 0.5);
+    assert!(!s.doc().unwrap().node(instance).unwrap().overrides.contains("opacity"));
+    run(&mut s, "node.set", json!({"id": component, "props": {"opacity": 0.25}}));
+    let n = s.doc().unwrap().node(instance).unwrap();
+    assert_eq!(n.opacity, 0.25, "the instance still follows its main");
+    assert!(!n.overrides.contains("opacity"));
+}
+
+#[test]
+fn outlining_a_main_layer_keeps_its_instance_override() {
+    let mut s = Session::new();
+    let frame = NodeId(run(&mut s, "frame.create", json!({"width": 100, "height": 100}))["id"].as_u64().unwrap());
+    let layer = NodeId(
+        run(
+            &mut s,
+            "shape.rectangle",
+            json!({
+                "parent": frame, "x": 24, "y": 24, "width": 64, "height": 64,
+                "props": {"fill": "#FF0000", "stroke": "#0000FF", "strokeWeight": 8}
+            }),
+        )["id"]
+            .as_u64()
+            .unwrap(),
+    );
+    let component = run(&mut s, "component.create", json!({"ids": [frame]}))["id"].clone();
+    run(&mut s, "instance.create", json!({"component": component, "x": 200}));
+    let copy = s.doc().unwrap().nodes().find(|n| n.source == Some(layer)).unwrap().id;
+    run(&mut s, "node.set", json!({"id": copy, "props": {"opacity": 0.25}}));
+    let before = s.doc().unwrap().clone();
+    let view = View { origin: (0.0, 0.0), scale: 1.0, width: 312, height: 112 };
+    let expected = render_view(&before, s.page().unwrap(), &view, &Options::default()).unwrap();
+    let group = outlined(&mut s, layer);
+    let doc = s.doc().unwrap();
+    let actual = render_view(doc, s.page().unwrap(), &view, &Options::default()).unwrap();
+    same_pixels(actual.data(), expected.data());
+    let instance_group = doc.node(copy).unwrap();
+    assert!(matches!(instance_group.kind, NodeKind::Group));
+    assert_eq!(instance_group.source, Some(group));
+    assert_eq!(instance_group.opacity, 0.25);
+    assert!(instance_group.overrides.contains("opacity"));
+    assert!(s.undo().unwrap());
+    assert_eq!(serde_json::to_value(s.doc().unwrap()).unwrap(), serde_json::to_value(&before).unwrap());
+    assert!(s.redo().unwrap());
+    let actual = render_view(s.doc().unwrap(), s.page().unwrap(), &view, &Options::default()).unwrap();
+    same_pixels(actual.data(), expected.data());
+}