feat(isaacsim): expose material sharing and task-local G1 fixture

src/unilab/base/backend_factory.py

@@ -91,6 +91,8 @@ def env_backend_kwargs(cfg: "EnvCfg") -> dict[str, Any]:
     # constructor never see an unknown keyword on the legacy default path.
     if cfg.isaacsim_tensor_cuda_ipc:
         result["isaacsim_tensor_cuda_ipc"] = True
+    if cfg.isaacsim_share_friction_materials:
+        result["share_friction_materials"] = True
     # Forward the explicit Genesis device id only when a rank selected one;
     # when absent, unisim-core's factory default applies and Genesis picks
     # its own device.

src/unilab/base/base.py

@@ -107,6 +107,11 @@ class EnvCfg:
     # remains false so legacy NumPy shared-memory behavior is unchanged until a
     # task owner explicitly negotiates the candidate tensor contract.
     isaacsim_tensor_cuda_ipc: bool = False
+    # Opt-in PhysX material sharing for large scenes.  Equal initial sliding
+    # friction values share a material and reset-time friction DR is disabled
+    # at capability negotiation.  Keep this false when complete per-geom/per-env
+    # friction DR is required.
+    isaacsim_share_friction_materials: bool = False
     # ``isaacsim`` PhysX solver overrides, forwarded to UniSim's bounded,
     # readback-validated PhysxSolverConfig (unilabsim/unisim#251, #259).
     # ``None`` keeps the PhysX scene defaults; the backend validates each
@@ -287,6 +292,11 @@ def validate(self):
             raise ValueError(
                 f"isaacsim_tensor_cuda_ipc must be a boolean, got {self.isaacsim_tensor_cuda_ipc!r}"
             )
+        if not isinstance(self.isaacsim_share_friction_materials, bool):
+            raise ValueError(
+                "isaacsim_share_friction_materials must be a boolean, got "
+                f"{self.isaacsim_share_friction_materials!r}"
+            )
         # PhysX accepts zero velocity iterations (its scene minimum is 0) but
         # requires at least one position iteration; mirror UniSim's
         # PhysxSolverConfig bounds here so owner configs fail fast.

tests/base/test_isaacsim_backend.py

@@ -148,6 +148,7 @@ def test_factory_routes_isaacsim_without_importing_kit(scene_file: str) -> None:
         ({"isaacsim_render_width": 0}, "isaacsim_render_width"),
         ({"isaacsim_render_height": True}, "isaacsim_render_height"),
         ({"isaacsim_tensor_cuda_ipc": 1}, "isaacsim_tensor_cuda_ipc"),
+        ({"isaacsim_share_friction_materials": 1}, "isaacsim_share_friction_materials"),
     ],
 )
 def test_env_cfg_rejects_invalid_isaacsim_render_settings(
@@ -219,6 +220,15 @@ def test_env_backend_kwargs_forwards_isaacsim_tensor_cuda_ipc() -> None:
     assert kwargs["isaacsim_tensor_cuda_ipc"] is True
 
 
+def test_env_backend_kwargs_forwards_isaacsim_material_sharing() -> None:
+    """Material sharing is an explicit benchmark/task opt-in, not a default."""
+    from unilab.base.backend_factory import env_backend_kwargs
+
+    assert "share_friction_materials" not in env_backend_kwargs(EnvCfg())
+    kwargs = env_backend_kwargs(EnvCfg(isaacsim_share_friction_materials=True))
+    assert kwargs["share_friction_materials"] is True
+
+
 def test_create_backend_rejects_legacy_isaacsim_tensor_cuda_ipc_runtime(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:

tests/config/test_g1_motion_tracking_owners.py

@@ -210,6 +210,7 @@ def test_flashsac_g1_motion_tracking_isaacsim_opts_into_cuda_ipc_candidate() ->
     assert cfg.training.sim_backend == "isaacsim"
     assert cfg.env.tensor_runtime is True
     assert cfg.env.isaacsim_tensor_cuda_ipc is True
+    assert cfg.env.isaacsim_share_friction_materials is True
 
     scene = cfg.env.scene
     assert scene.model_file is None
@@ -269,6 +270,7 @@ def test_isaacsim_tensor_fixture_materializes_into_manager_config() -> None:
 
     cfg.validate()
     assert cfg.isaacsim_tensor_cuda_ipc is True
+    assert cfg.isaacsim_share_friction_materials is True
     assert cfg.tensor_runtime is True
     assert cfg.scene is not None
     assert cfg.scene.entity_assets

tests/fixtures/isaacsim_g1_tensor_cuda_ipc/flat_floor_entity.xml

@@ -2,7 +2,9 @@
   <option integrator="implicitfast" timestep="0.006666666666666667"/>
   <worldbody>
     <body name="floor">
-      <geom name="floor" type="box" size="100 100 0.05" pos="0 0 -0.05" mass="1"/>
+      <!-- Task-local finite support avoids inter-env broadphase overlap while retaining
+           stable box-contact semantics that the zero-size-plane import lacked. -->
+      <geom name="floor" type="box" size="0.25 0.25 0.05" pos="0 0 -0.05" mass="1"/>
     </body>
   </worldbody>
 </mujoco>

tests/fixtures/isaacsim_g1_tensor_cuda_ipc/isaacsim_candidate_overlay.yaml

@@ -14,8 +14,11 @@ training:
 env:
   tensor_runtime: true
   isaacsim_device_id: 0
-  isaacsim_worker_timeout_s: 120.0
+  isaacsim_worker_timeout_s: 300.0
   isaacsim_tensor_cuda_ipc: true
+  # This throughput fixture does not use geom-friction reset DR. Sharing equal
+  # initial native materials keeps 2048 clones below PhysX's 64K material cap.
+  isaacsim_share_friction_materials: true
   scene:
     # IsaacSim consumes the mapped physical-scene profile.  The task source,
     # not an all-zero EntityInitialState, remains authoritative for the 29

tests/scripts/test_g1_flashsac_backend.py

@@ -116,6 +116,8 @@ def fake_create_backend(
 
     assert captured["backend_type"] == backend
     assert captured["base_name"] == expected
+    if backend == "isaacsim":
+        assert captured["share_friction_materials"] is True
 
 
 def test_build_backend_binds_newton_process_device_before_construction(