Add visual handle rebuild hook

src/mjviser/scene.py

@@ -274,6 +274,38 @@ def set_refresh_handler(self, handler: Callable[[], None] | None) -> None:
     with self._update_lock:
       self._refresh_handler = handler
 
+  def rebuild_visual_handles(self) -> None:
+    """Rebuild handles whose geometry or appearance is baked at creation time."""
+    with self._update_lock:
+      for group in self._mesh_groups:
+        group.handle.remove()
+      self._mesh_groups.clear()
+
+      for handle in self._fixed_geom_handles.values():
+        handle.remove()
+      self._fixed_geom_handles.clear()
+
+      for handle in self._fixed_site_handles.values():
+        handle.remove()
+      self._fixed_site_handles.clear()
+
+      for handle in self.site_handles_by_group.values():
+        handle.remove()
+      self.site_handles_by_group.clear()
+
+      self._clear_hull_handles()
+      self._hull_body_meshes.clear()
+      self._hull_mesh_bodies.clear()
+
+      mujoco.mj_kinematics(self.mj_model, self.mj_data)
+      self._add_fixed_geometry()
+      self._create_mesh_handles_by_group()
+      self._add_fixed_sites()
+      self._create_site_handles_by_group()
+      self._compute_hull_body_meshes()
+      self._build_hull_handles()
+      self._sync_visibilities()
+
   def _apply_visualization_change(self, mutator: Callable[[], None]) -> None:
     """Apply a GUI-side visualization change and refresh from cached state."""
     refresh_handler: Callable[[], None] | None = None

tests/test_scene.py

@@ -125,6 +125,21 @@ def test_scene_default_visibility(scene):
   assert scene.geom_groups_visible[3:] == [False, False, False]
 
 
+def test_rebuild_visual_handles_recreates_baked_mesh_handles(scene, simple_model):
+  old_handles = [group.handle for group in scene._mesh_groups]
+  assert old_handles
+
+  box_id = mujoco.mj_name2id(simple_model, mujoco.mjtObj.mjOBJ_GEOM, "box")
+  simple_model.geom_rgba[box_id] = [0.0, 0.0, 1.0, 1.0]
+
+  scene.rebuild_visual_handles()
+
+  new_handles = [group.handle for group in scene._mesh_groups]
+  assert new_handles
+  old_handle_ids = {id(handle) for handle in old_handles}
+  assert all(id(handle) not in old_handle_ids for handle in new_handles)
+
+
 # Batched transform---------------------------------------------------