Extrude and Revolve To Object on curved faces follow the face: the tool runs through the target body and is cut back to its surface (the piece that starts at the profile); tests against a cylinder and a sphere (volumes by integration) and a revolve ending on a post; Shell Outside/Both on a cylinder through the exact curved offsets

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/engine/src/extent_tests.rs

@@ -0,0 +1,106 @@
+//! To Object extents on curved targets, and shells outside/both on curved bodies.
+
+use std::f64::consts::PI;
+
+use serde_json::{Value, json};
+
+use crate::Session;
+
+fn run(s: &mut Session, id: &str, p: Value) -> Value {
+    match s.execute(id, &p) {
+        Ok(v) => v,
+        Err(e) => panic!("{id} {p}: {e}"),
+    }
+}
+
+fn body(s: &mut Session, b: &str) -> Value {
+    run(s, "inspect.measure", json!({ "bodies": [b] }))["bodies"][0].clone()
+}
+
+/// A square post extruded up to a horizontal cylinder (axis along x, r 10, centre z 30): its
+/// top takes the cylinder's shape, so the post is shortest in the middle.
+#[test]
+fn extrude_to_a_cylinder_follows_it() {
+    let mut s = Session::default();
+    run(&mut s, "solid.cylinder", json!({"base": [-20, 0, 30], "axis": [1, 0, 0], "radius": 10, "height": 40, "body_name": "Bar"}));
+    run(&mut s, "sketch.create", json!({"plane": "XY", "name": "P"}));
+    run(&mut s, "sketch.rectangle.two_point", json!({"p0": [-4, -4], "p1": [4, 4]}));
+    run(&mut s, "sketch.finish", json!({}));
+    run(&mut s, "solid.extrude", json!({"sketch": "P", "to": [0, 0, 20], "body_name": "Post"}));
+    let b = body(&mut s, "Post");
+    // Highest at the post's sides (y = ±4): z = 30 − √(100 − 16); the volume follows the arc.
+    let top = b["bbox"]["max"][2].as_f64().unwrap_or(0.0);
+    assert!((top - (30.0 - (100.0f64 - 16.0).sqrt())).abs() < 1e-3, "{b}");
+    // ∫ over y of (30 − √(100 − y²)) × 8 (x width), y from −4 to 4.
+    let n = 2000;
+    let want: f64 = (0..n).map(|i| -4.0 + 8.0 * (i as f64 + 0.5) / n as f64).map(|y| (30.0 - (100.0 - y * y).sqrt()) * 8.0 * 8.0 / n as f64).sum();
+    assert!((b["volume_mm3"].as_f64().unwrap_or(0.0) - want).abs() < want * 2e-3, "{} vs {want}", b["volume_mm3"]);
+}
+
+/// A round post extruded up to a sphere (r 15 at z 40): it stops on the sphere's underside.
+#[test]
+fn extrude_to_a_sphere_follows_it() {
+    let mut s = Session::default();
+    run(&mut s, "solid.sphere", json!({"center": [0, 0, 40], "radius": 15, "body_name": "Ball"}));
+    run(&mut s, "sketch.create", json!({"plane": "XY", "name": "P"}));
+    run(&mut s, "sketch.circle.center", json!({"center": [0, 0], "radius": 5}));
+    run(&mut s, "sketch.finish", json!({}));
+    run(&mut s, "solid.extrude", json!({"sketch": "P", "to": [0, 0, 25], "body_name": "Post"}));
+    let b = body(&mut s, "Post");
+    let top = b["bbox"]["max"][2].as_f64().unwrap_or(0.0);
+    assert!((top - (40.0 - (225.0f64 - 25.0).sqrt())).abs() < 1e-2, "{b}");
+    // Volume: cylinder to z 25 plus the ring between the sphere cap and the plane z = 25.
+    let cap = |r: f64| 40.0 - (225.0 - r * r).sqrt();
+    let n = 2000;
+    let want: f64 = (0..n).map(|i| 5.0 * (i as f64 + 0.5) / n as f64).map(|r| cap(r) * 2.0 * PI * r * 5.0 / n as f64).sum();
+    assert!((b["volume_mm3"].as_f64().unwrap_or(0.0) - want).abs() < want * 2e-3, "{} vs {want}", b["volume_mm3"]);
+}
+
+/// Shell Outside and Both on a cylinder (open top): exact offsets of the curved wall.
+#[test]
+fn shell_outside_and_both_on_a_cylinder() {
+    let shell = |dir: &str| {
+        let mut s = Session::default();
+        run(&mut s, "solid.cylinder", json!({"radius": 10, "height": 20, "body_name": "C"}));
+        run(&mut s, "solid.shell", json!({"faces": [[0, 0, 20]], "thickness": 2, "direction": dir}));
+        body(&mut s, "C")["volume_mm3"].as_f64().unwrap_or(0.0)
+    };
+    let out = PI * (144.0 * 22.0 - 100.0 * 20.0);
+    assert!((shell("outside") - out).abs() < out * 1e-3, "{} vs {out}", shell("outside"));
+    let both = PI * (121.0 * 21.0 - 81.0 * 19.0);
+    assert!((shell("both") - both).abs() < both * 1e-3, "{} vs {both}", shell("both"));
+}
+
+/// A ring section revolved To Object up to a post standing in its path: it ends on the post's
+/// round side (touching, not overlapping), between first contact and the post's centre.
+#[test]
+fn revolve_to_a_cylinder_follows_it() {
+    for side in [1.0, -1.0] {
+        let mut s = Session::default();
+        run(&mut s, "solid.cylinder", json!({"base": [0, 14.0 * side, -5], "radius": 4, "height": 15, "body_name": "Post"}));
+        run(&mut s, "sketch.create", json!({"plane": "XZ", "name": "S"}));
+        run(&mut s, "sketch.line", json!({"points": [[10, 0], [15, 0], [15, 5], [10, 5]], "closed": true}));
+        run(&mut s, "sketch.finish", json!({}));
+        let r = s.execute("solid.revolve", &json!({"sketch": "S", "axis": "y", "to": [4, 14.0 * side, 2], "body_name": "Arc"}));
+        if r.is_err() {
+            continue; // the post on the side the revolve turns away from is past the turn
+        }
+        let st = s.model.state();
+        let (arc, post) = (st.body("Arc").unwrap(), st.body("Post").unwrap());
+        let overlap = solvecraft_kernel::boolean(&arc.body, &post.body, solvecraft_kernel::BoolOp::Intersect)
+            .ok()
+            .flatten()
+            .map(|b| solvecraft_kernel::measure(&b).map(|m| m.volume).unwrap_or(0.0))
+            .unwrap_or(0.0);
+        assert!(overlap < 1e-3, "no overlap: {overlap}");
+        let v = solvecraft_kernel::measure(&arc.body).unwrap().volume;
+        let full = PI * (225.0 - 100.0) * 5.0;
+        // The post is at a quarter turn one way (three quarters the other): the ring stops
+        // short of the post's centre line, within its half-width of it.
+        let turned = v / full * 360.0;
+        let to_centre = if turned < 180.0 { 90.0 } else { 270.0 };
+        assert!(turned < to_centre && turned > to_centre - 30.0, "{turned}°");
+        return;
+    }
+    panic!("neither post was reached");
+}

crates/engine/src/lib.rs

@@ -425,5 +425,7 @@ impl Session {
     }
 }
 
+#[cfg(test)]
+mod extent_tests;
 #[cfg(test)]
 mod tests;