Modelled threads (Thread with modeled: true): the ISO 68-1 profile cut along a helix, M3 to M20, on shafts and in bores; running out past a free end of the face, stopping square at a set length. The groove is a watertight screw-sweep mesh (kernel::sweep_helix_mesh) cut by kernel::faceted_boolean (BSP on the faceted body, tolerance ladder checked by A−B + A∩B = A); the polygon rebuild welds vertices across grid cells, splits pinched loops, finds T-junctions through a grid, and takes the group's plane for a loop a hair off flat

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

crates/engine/src/cmd/features.rs

@@ -1131,7 +1131,8 @@ fn thread(s: &mut Session, p: &Value) -> Result<Value> {
     if let Some(l) = &length {
         check_expr(s, l, Kind::Length, cmd, "length")?;
     }
-    let v = add_feature(s, p, FeatureKind::Thread { face, designation, length })?;
+    let modeled = p.get("modeled").and_then(Value::as_bool).unwrap_or(false);
+    let v = add_feature(s, p, FeatureKind::Thread { face, designation, length, modeled })?;
     let st = s.model.state();
     let t = v.get("feature").and_then(Value::as_u64).and_then(|id| st.threads.iter().find(|t| t.feature == id).cloned());
     Ok(json!({"feature": v.get("feature"), "name": v.get("name"), "thread": t}))