Persistent naming: joint origins on faces and circular ends, and face appearances, store the face's name and find it by name first (a joint whose face is gone reports it instead of attaching elsewhere)

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

crates/engine/src/cmd/inspect.rs

@@ -354,6 +354,16 @@ fn appearance(s: &mut Session, p: &Value) -> Result<Value> {
     if bodies.is_empty() && faces.is_empty() && comps.is_empty() {
         return Err(bad(cmd, "give `bodies`, `faces` or `components`"));
     }
+    // Persistent names of the picked faces.
+    let st_names: Vec<(String, solvecraft_geom::Vec3, Option<String>)> = faces
+        .iter()
+        .map(|(b, pt)| {
+            let n = st.body(b).and_then(|mb| {
+                solvecraft_doc::appearance::face_index_at(mb, *pt).and_then(|i| solvecraft_doc::naming::face_names(mb).get(i).cloned())
+            });
+            (b.clone(), *pt, n)
+        })
+        .collect();
     let a = &mut s.doc_mut().appearances;
     for b in &bodies {
         match &look {
@@ -368,7 +378,8 @@ fn appearance(s: &mut Session, p: &Value) -> Result<Value> {
             if a.faces.len() >= 100_000 {
                 return Err(bad(cmd, "too many face appearances"));
             }
-            a.faces.push(FaceLook { body: body.clone(), point: *pt, look: l.clone() });
+            let name = st_names.iter().find(|(b, p, _)| b == body && p.dist(*pt) < 1e-12).and_then(|(_, _, n)| n.clone());
+            a.faces.push(FaceLook { body: body.clone(), point: *pt, look: l.clone(), name });
         }
     }
     for c in &comps {

crates/engine/src/cmd/joints.rs

@@ -131,8 +131,11 @@ fn origin_param(s: &Session, v: Option<&Value>, cmd: &str) -> Result<JointOrigin
     let local = |p: Vec3| solvecraft_doc::apply_point(&inv, p);
     let local_dir = |d: Vec3| solvecraft_doc::apply_vector(&inv, d);
     let snap = match what {
-        "face" => Snap::FaceCenter { pick: local(world) },
-        "circle" => Snap::CircleCenter { pick: local(world) },
+        "face" | "circle" => {
+            let pick = local(world);
+            let face = solvecraft_doc::naming::face_names_at(&s.model.state(), &[pick]).into_iter().next().filter(|n| !n.is_empty());
+            if what == "face" { Snap::FaceCenter { pick, face } } else { Snap::CircleCenter { pick, face } }
+        }
         "point" => Snap::Point { point: local(world), z: v.get("z").and_then(vec3).map(local_dir) },
         _ => {
             let f = v.get("frame").cloned().unwrap_or_default();