Joints engine: joint origins that snap to faces, round ends or points (re-found on every solve, so joints follow edits), joints (rigid, revolute, slider, cylindrical, pin-slot, planar, ball) with values, limits, flip and offset, As-built Joint, Rigid Group, Drive Joints, Motion Link, a joint-graph solver from grounded occurrences (degrees of freedom per occurrence, loop conflicts reported), Interference between bodies

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

crates/engine/src/lib.rs

@@ -249,6 +249,10 @@ impl Session {
     pub fn refresh(&mut self) {
         self.model.evaluate(&self.doc);
         self.revision += 1;
+        // Joints follow the geometry their origins snap to.
+        if !self.doc.assembly.joints.is_empty() {
+            cmd::joints::resolve(self);
+        }
         if let Some(id) = self.active_sketch
             && self.doc.feature(id).is_none()
         {