fix: IS 4.1.0 + Blackwell GPU compatibility fixes

- Add scipy Rotation scalar_first monkey-patch for older scipy (<1.11)
- Fix SimulationApp import to support both IS 4.x and 5.x
- Reuse task object across reset() calls to prevent duplicate prims
- Add _scene_initialized guard in set_up_scene() for repeated resets
- Cache arena_file_path to survive task_cfg.pop()
- Clean up collision groups before re-creating
- Switch to PathTracing renderer for clean output on Blackwell GPU

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

workflows/simbox/core/tasks/banana.py

@@ -63,6 +63,17 @@ class BananaBaseTask(BaseTask):
         self._defaultFluidPath = Sdf.Path("/World/task_0/fulid")
 
     def set_up_scene(self, scene: Scene) -> None:
+        # Skip re-initialization if scene is already set up (repeated reset() calls)
+        if getattr(self, '_scene_initialized', False):
+            self._task_objects = {}
+            self._task_objects |= (
+                getattr(self, 'fixtures', {}) |
+                getattr(self, 'objects', {}) |
+                getattr(self, 'robots', {}) |
+                getattr(self, 'cameras', {})
+            )
+            return
+        self._scene_initialized = True
         super().set_up_scene(scene)
         self._set_envmap()
         self.cfg = update_scenes(self.cfg)

workflows/simbox/core/utils/collision_utils.py

@@ -27,6 +27,11 @@ def filter_collisions(
     # We invert the collision group filters for more efficient collision filtering across environments
     physx_scene.CreateInvertCollisionGroupFilterAttr().Set(True)
 
+    # Clean up existing collision groups before re-creating (handles repeated reset() calls)
+    collision_prim = stage.GetPrimAtPath(collision_root_path)
+    if collision_prim.IsValid():
+        stage.RemovePrim(collision_root_path)
+
     UsdGeom.Scope.Define(stage, collision_root_path)
 
     with Sdf.ChangeBlock():

workflows/simbox_dual_workflow.py

@@ -45,6 +45,7 @@ class SimBoxDualWorkFlow(NimbusWorkFlow):
         self.scene_info = scene_info
         self.step_replay = False
         self.random_seed = random_seed
+        self._arena_file_path = None
         super().__init__(world, task_cfg_path)
 
     def parse_task_cfgs(self, task_cfg_path: str) -> list:
@@ -76,7 +77,8 @@ class SimBoxDualWorkFlow(NimbusWorkFlow):
 
         set_camera_view(eye=[1.3, 0.7, 2.7], target=[0.0, 0, 1.5], camera_prim_path="/OmniverseKit_Persp")
         # Modify config
-        arena_file_path = self.task_cfg.get("arena_file", None)
+        arena_file_path = self.task_cfg.get("arena_file", None) or self._arena_file_path
+        self._arena_file_path = arena_file_path
         with open(arena_file_path, "r", encoding="utf-8") as arena_file:
             arena = yaml.load(arena_file, Loader=Loader)
 
@@ -113,9 +115,13 @@ class SimBoxDualWorkFlow(NimbusWorkFlow):
             physx_interface = acquire_physx_interface()
             physx_interface.overwrite_gpu_setting(1)
 
-        self.task = get_task_cls(self.task_cfg["task"])(self.task_cfg)
+        if not hasattr(self, "task") or self.task is None:
+            self.task = get_task_cls(self.task_cfg["task"])(self.task_cfg)
+        else:
+            self.task.cfg = self.task_cfg
         self.stage = self.world.stage
         self.stage.SetDefaultPrim(self.stage.GetPrimAtPath("/World"))
+        self.world._current_tasks.clear()
         self.world.add_task(self.task)
 
         # # Add hidden ground plane for physics simulation