fix

Author: ooctipus

source/isaaclab/isaaclab/scene/interactive_scene.py

@@ -215,7 +215,7 @@ def __init__(self, cfg: InteractiveSceneCfg):
             if self.cfg.filter_collisions and "physx" in self.physics_backend:
                 self.filter_collisions(self._global_prim_paths)
 
-    def _build_clone_plan_from_cfg(self) -> cloner.ClonePlan:
+    def _build_clone_plan_from_cfg(self) -> cloner.ClonePlan | None:
         """Build a clone plan from scene cfg spawn variants and write planned spawn paths."""
 
         def num_variants(spawn_cfg) -> int:
@@ -251,6 +251,9 @@ def set_spawn_paths(spawn_cfg, paths: list[str | None]) -> None:
                     raise ValueError(f"Spawner at '{prim_path}' must have at least one variant.")
                 groups.append((cfg.spawn, prim_path.replace(self.env_regex_ns, self.env_fmt), count))
 
+        if not groups:
+            return None
+
         # Homogeneous scenes still spawn sources at env_0, but publish the simpler env-root plan.
         if all(count == 1 for _, _, count in groups):
             for spawn_cfg, destination, _ in groups: