3D sketch: with 3D Sketch on, the Line, Spline and Point tools take points off the sketch plane, snapping to model vertices, edges and faces and to drawn 3D points (segments that stay on the plane are ordinary sketch lines); drawn 3D curves are wires with fit points (sketch.line3d, sketch.spline3d: centripetal Catmull-Rom, sketch.point3d), a clicked 3D point gets a move triad (drag along X/Y/Z or parallel to the sketch plane: sketch.move3d, joined ends move together), Delete removes it; sweep and pipe paths may mix 3D curves with sketch curves; control: ui.triad, ui.worldToScreen

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/ui-egui/src/control.rs

@@ -207,6 +207,30 @@ pub fn handle(app: &mut SolveApp, ctx: &egui::Context, req: &ControlRequest) ->
             "dimension_selected": crate::dim_view::selected(app),
             "dimension_editing": crate::dim_view::editing(),
         })),
+        "ui.triad" => {
+            // Screen points of the 3D move triad's handles (x, y, z arrows and the plane square).
+            let Some(rect) = app.viewport.rect else { return err("no viewport") };
+            let proj = crate::viewport::projection(app, rect);
+            ok(json!(
+                crate::sketch3d::handle_points(app, &proj).into_iter().map(|(n, p)| json!({"handle": n, "x": p.x, "y": p.y})).collect::<Vec<_>>()
+            ))
+        }
+        "ui.worldToScreen" => {
+            let Some(rect) = app.viewport.rect else { return err("no viewport") };
+            let proj = crate::viewport::projection(app, rect);
+            let pts: Vec<Value> = p
+                .get("points")
+                .and_then(Value::as_array)
+                .into_iter()
+                .flatten()
+                .take(1000)
+                .map(|v| {
+                    let c = |i: usize| v.get(i).and_then(Value::as_f64).unwrap_or(0.0);
+                    proj.to_screen(solvecraft_engine::geom::Vec3::new(c(0), c(1), c(2))).map_or(Value::Null, |q| json!([q.x, q.y]))
+                })
+                .collect();
+            ok(json!(pts))
+        }
         "ui.sketchToScreen" => {
             // Screen points of active-sketch coordinates (for driving sketch interaction).
             let st = app.session.model.state();