feat: add fabric_read/fabric_write context managers to FabricFrameView

source/isaaclab/isaaclab/sensors/camera/camera.py

@@ -19,7 +19,7 @@
 import isaaclab.utils.sensors as sensor_utils
 from isaaclab.app.settings_manager import get_settings_manager
 from isaaclab.renderers import BaseRenderer, Renderer
-from isaaclab.sim.views import FrameView
+from isaaclab.sim.views import UsdFrameView
 from isaaclab.utils import has_kit, to_camel_case
 from isaaclab.utils.math import (
     convert_camera_frame_orientation_convention,
@@ -405,9 +405,11 @@ def _initialize_impl(self):
         # references to prims located in the stage.
         self._renderer.prepare_stage(self.stage, self._num_envs)
 
-        # Create a view for the sensor with Fabric enabled for fast pose queries.
-        # TODO: remove sync_usd_on_fabric_write=True once the GPU Fabric sync bug is fixed.
-        self._view = FrameView(self.cfg.prim_path, device=self._device, stage=self.stage, sync_usd_on_fabric_write=True)
+        # Camera uses UsdFrameView directly (not FrameView/FabricFrameView) because
+        # the RTX renderer / Replicator reads camera poses from USD prim paths, not
+        # from Fabric.  Writing to Fabric + sync_usd_on_fabric_write was wasteful —
+        # this bypasses Fabric entirely for camera transforms.
+        self._view = UsdFrameView(self.cfg.prim_path, device=self._device, stage=self.stage)
         # Check that sizes are correct
         if self._view.count != self._num_envs:
             raise RuntimeError(

source/isaaclab/isaaclab/sim/views/usd_frame_view.py

@@ -71,8 +71,7 @@ def __init__(
             stage: USD stage to search for prims. Defaults to None, in which case the current
                 active stage from the simulation context is used.
             **kwargs: Additional keyword arguments (ignored). Allows forward-compatible
-                construction when callers pass backend-specific options like
-                ``sync_usd_on_fabric_write``.
+                construction when callers pass backend-specific options.
 
         Raises:
             ValueError: If any matched prim is not Xformable or doesn't have standardized

source/isaaclab/test/sensors/test_tiled_camera.py

@@ -195,3 +195,79 @@ def _populate_scene():
         sim_utils.define_rigid_body_properties(prim_path, sim_utils.RigidBodyPropertiesCfg())
         sim_utils.define_mass_properties(prim_path, sim_utils.MassPropertiesCfg(mass=5.0))
         sim_utils.define_collision_properties(prim_path, sim_utils.CollisionPropertiesCfg())
+
+
+# ------------------------------------------------------------------
+# Camera pose → render validation (PrepareForReuse / Fabric path)
+# ------------------------------------------------------------------
+
+
+@pytest.mark.parametrize(
+    "device, camera_cls",
+    [
+        pytest.param("cpu", TiledCamera, id="cpu-tiled"),
+        pytest.param("cpu", Camera, id="cpu-non_tiled"),
+        pytest.param("cuda:0", TiledCamera, id="cuda:0-tiled"),
+        pytest.param("cuda:0", Camera, id="cuda:0-non_tiled"),
+    ],
+)
+def test_camera_pose_update_reflected_in_render(setup_camera, device, camera_cls):
+    """Camera pose changes via FrameView should be visible in rendered depth.
+
+    Moves camera close then far, renders depth, and verifies that the mean
+    valid depth from the far position is significantly larger (>1.5×) than
+    the close position.  This validates that Fabric-side pose writes
+    (via PrepareForReuse) or USD writes are correctly propagated to the
+    RTX renderer.
+    """
+    sim, _unused_cam_cfg, dt = setup_camera
+
+    cam_cfg = CameraCfg(
+        prim_path="/World/PoseTestCam",
+        height=128,
+        width=256,
+        update_period=0,
+        update_latest_camera_pose=True,
+        data_types=["distance_to_camera"],
+        spawn=sim_utils.PinholeCameraCfg(
+            focal_length=24.0,
+            focus_distance=400.0,
+            horizontal_aperture=20.955,
+            clipping_range=(0.1, 1.0e5),
+        ),
+    )
+    camera = camera_cls(cam_cfg)
+    sim.reset()
+
+    target = torch.tensor([[0.0, 0.0, 0.0]], dtype=torch.float32, device=camera.device)
+    max_range = cam_cfg.spawn.clipping_range[1]
+
+    # -- close position --
+    eyes_close = torch.tensor([[2.0, 2.0, 2.0]], dtype=torch.float32, device=camera.device)
+    camera.set_world_poses_from_view(eyes_close, target)
+    sim.step()
+    camera.update(dt)
+    depth_close = camera.data.output["distance_to_camera"].clone()
+
+    # -- far position --
+    eyes_far = torch.tensor([[8.0, 8.0, 8.0]], dtype=torch.float32, device=camera.device)
+    camera.set_world_poses_from_view(eyes_far, target)
+    sim.step()
+    camera.update(dt)
+    depth_far = camera.data.output["distance_to_camera"].clone()
+
+    # -- validate --
+    valid_close = depth_close[depth_close < max_range]
+    valid_far = depth_far[depth_far < max_range]
+
+    assert valid_close.numel() > 0, "No valid close-range depth pixels"
+    assert valid_far.numel() > 0, "No valid far-range depth pixels"
+
+    mean_close = valid_close.mean().item()
+    mean_far = valid_far.mean().item()
+
+    assert mean_far > mean_close * 1.5, (
+        f"Far depth ({mean_far:.2f}) should be > 1.5× close depth ({mean_close:.2f}). "
+        "Camera pose change may not be reaching the renderer."
+    )
+    del camera

source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py

@@ -50,6 +50,10 @@ class FabricFrameView(BaseFrameView):
     Warp kernels operating on ``omni:fabric:worldMatrix``.  All other operations
     delegate to the internal USD view.
 
+    After every Fabric write, :meth:`PrepareForReuse` is called on the
+    ``PrimSelection`` to notify the renderer (FSD/Storm) that Fabric data
+    has changed.
+
     All getters return ``wp.array``.  Setters accept ``wp.array``.
     """
 
@@ -58,12 +62,11 @@ def __init__(
         prim_path: str,
         device: str = "cpu",
         validate_xform_ops: bool = True,
-        sync_usd_on_fabric_write: bool = False,
         stage: Usd.Stage | None = None,
+        **kwargs,
     ):
         self._usd_view = UsdFrameView(prim_path, device=device, validate_xform_ops=validate_xform_ops, stage=stage)
         self._device = device
-        self._sync_usd_on_fabric_write = sync_usd_on_fabric_write
 
         settings = SettingsManager.instance()
         self._use_fabric = bool(settings.get("/physics/fabricEnabled", False))
@@ -134,6 +137,8 @@ def set_world_poses(self, positions=None, orientations=None, indices=None):
         if not self._fabric_initialized:
             self._initialize_fabric()
 
+        self._prepare_for_reuse()
+
         indices_wp = self._resolve_indices_wp(indices)
         count = indices_wp.shape[0]
 
@@ -165,8 +170,6 @@ def set_world_poses(self, positions=None, orientations=None, indices=None):
 
         self._fabric_hierarchy.update_world_xforms()
         self._fabric_usd_sync_done = True
-        if self._sync_usd_on_fabric_write:
-            self._usd_view.set_world_poses(positions, orientations, indices)
 
     def get_world_poses(self, indices=None):
         if not self._use_fabric:
@@ -177,6 +180,8 @@ def get_world_poses(self, indices=None):
         if not self._fabric_usd_sync_done:
             self._sync_fabric_from_usd_once()
 
+        self._prepare_for_reuse()
+
         indices_wp = self._resolve_indices_wp(indices)
         count = indices_wp.shape[0]
 
@@ -228,6 +233,8 @@ def set_scales(self, scales, indices=None):
         if not self._fabric_initialized:
             self._initialize_fabric()
 
+        self._prepare_for_reuse()
+
         indices_wp = self._resolve_indices_wp(indices)
         count = indices_wp.shape[0]
 
@@ -255,8 +262,6 @@ def set_scales(self, scales, indices=None):
 
         self._fabric_hierarchy.update_world_xforms()
         self._fabric_usd_sync_done = True
-        if self._sync_usd_on_fabric_write:
-            self._usd_view.set_scales(scales, indices)
 
     def get_scales(self, indices=None):
         if not self._use_fabric:
@@ -267,6 +272,8 @@ def get_scales(self, indices=None):
         if not self._fabric_usd_sync_done:
             self._sync_fabric_from_usd_once()
 
+        self._prepare_for_reuse()
+
         indices_wp = self._resolve_indices_wp(indices)
         count = indices_wp.shape[0]
 
@@ -294,6 +301,93 @@ def get_scales(self, indices=None):
             wp.synchronize()
         return scales_wp
 
+    # ------------------------------------------------------------------
+    # Internal — PrepareForReuse (renderer notification + topology tracking)
+    # ------------------------------------------------------------------
+
+    def _prepare_for_reuse(self) -> None:
+        """Call PrepareForReuse on the PrimSelection to notify the renderer.
+
+        PrepareForReuse serves two purposes:
+
+        1. **Renderer notification**: Tells FSD/Storm that Fabric data has
+           been (or will be) modified, so the next rendered frame reflects
+           the updated transforms.
+        2. **Topology change detection**: Returns True when Fabric's
+           internal memory layout changed (e.g., prims added/removed).
+           In that case, view-to-fabric index mappings and fabricarrays
+           must be rebuilt.
+        """
+        if self._fabric_selection is None:
+            return
+
+        topology_changed = self._fabric_selection.PrepareForReuse()
+        if topology_changed:
+            logger.info("Fabric topology changed — rebuilding view-to-fabric index mapping.")
+            self._rebuild_fabric_arrays()
+
+    def _rebuild_fabric_arrays(self) -> None:
+        """Rebuild fabricarray and view↔fabric mappings after a topology change."""
+        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=self._fabric_device)
+        self._fabric_to_view = wp.fabricarray(self._fabric_selection, self._view_index_attr)
+
+        wp.launch(
+            kernel=fabric_utils.set_view_to_fabric_array,
+            dim=self._fabric_to_view.shape[0],
+            inputs=[self._fabric_to_view, self._view_to_fabric],
+            device=self._fabric_device,
+        )
+        wp.synchronize()
+
+        self._fabric_world_matrices = wp.fabricarray(self._fabric_selection, "omni:fabric:worldMatrix")
+
+    # ------------------------------------------------------------------
+    # Context managers for raw Fabric access
+    # ------------------------------------------------------------------
+
+    def fabric_write(self):
+        """Context manager for raw Fabric write operations.
+
+        Calls ``PrepareForReuse()`` on entry (notifying the renderer that
+        data is about to change) and ``update_world_xforms()`` +
+        ``PrepareForReuse()`` on exit (propagating changes through the
+        hierarchy).
+
+        Example::
+
+            with view.fabric_write() as fab:
+                # fab.world_matrices is the fabricarray
+                wp.launch(my_kernel, dim=N, inputs=[fab.world_matrices, ...])
+        """
+        return _FabricWriteContext(self)
+
+    def fabric_read(self):
+        """Context manager for raw Fabric read operations.
+
+        Calls ``PrepareForReuse()`` on entry to ensure the view’s
+        fabricarray pointers are still valid after potential topology
+        changes.
+
+        Example::
+
+            with view.fabric_read() as fab:
+                wp.launch(my_read_kernel, dim=N, inputs=[fab.world_matrices, ...])
+        """
+        return _FabricReadContext(self)
+
+    @property
+    def world_matrices(self) -> wp.fabricarray | None:
+        """The raw Fabric world-matrix array (read-only property).
+
+        Returns None if Fabric is not initialized.
+        """
+        return getattr(self, "_fabric_world_matrices", None)
+
+    @property
+    def view_to_fabric_mapping(self) -> wp.array | None:
+        """View-index → Fabric-index mapping array."""
+        return getattr(self, "_view_to_fabric", None)
+
     # ------------------------------------------------------------------
     # Internal — Fabric initialization
     # ------------------------------------------------------------------
@@ -384,11 +478,8 @@ def _sync_fabric_from_usd_once(self) -> None:
         positions_usd, orientations_usd = self._usd_view.get_world_poses()
         scales_usd = self._usd_view.get_scales()
 
-        prev_sync = self._sync_usd_on_fabric_write
-        self._sync_usd_on_fabric_write = False
         self.set_world_poses(positions_usd, orientations_usd)
         self.set_scales(scales_usd)
-        self._sync_usd_on_fabric_write = prev_sync
 
         self._fabric_usd_sync_done = True
 
@@ -401,3 +492,90 @@ def _resolve_indices_wp(self, indices: wp.array | None) -> wp.array:
         if indices.dtype != wp.uint32:
             return wp.array(indices.numpy().astype("uint32"), dtype=wp.uint32, device=self._device)
         return indices
+
+
+# ======================================================================
+# Context manager helpers (module-level, not inside FabricFrameView)
+# ======================================================================
+
+
+class _FabricWriteContext:
+    """RAII context manager for Fabric write operations.
+
+    On entry: ensures Fabric is initialized, calls PrepareForReuse.
+    On exit (no exception): synchronizes, propagates hierarchy, marks sync done.
+    """
+
+    __slots__ = ("_view",)
+
+    def __init__(self, view: FabricFrameView):
+        self._view = view
+
+    def __enter__(self):
+        if not self._view._fabric_initialized:
+            self._view._initialize_fabric()
+        if not self._view._fabric_usd_sync_done:
+            self._view._sync_fabric_from_usd_once()
+        self._view._prepare_for_reuse()
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        if exc_type is None:
+            wp.synchronize()
+            self._view._fabric_hierarchy.update_world_xforms()
+            self._view._fabric_usd_sync_done = True
+        return False
+
+    @property
+    def world_matrices(self) -> wp.fabricarray:
+        """The fabricarray of omni:fabric:worldMatrix."""
+        return self._view._fabric_world_matrices
+
+    @property
+    def view_to_fabric(self) -> wp.array:
+        """View-index to Fabric-index mapping."""
+        return self._view._view_to_fabric
+
+    @property
+    def count(self) -> int:
+        """Number of prims in the view."""
+        return self._view.count
+
+
+class _FabricReadContext:
+    """RAII context manager for Fabric read operations.
+
+    On entry: ensures Fabric is initialized, calls PrepareForReuse.
+    On exit: no-op.
+    """
+
+    __slots__ = ("_view",)
+
+    def __init__(self, view: FabricFrameView):
+        self._view = view
+
+    def __enter__(self):
+        if not self._view._fabric_initialized:
+            self._view._initialize_fabric()
+        if not self._view._fabric_usd_sync_done:
+            self._view._sync_fabric_from_usd_once()
+        self._view._prepare_for_reuse()
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        return False
+
+    @property
+    def world_matrices(self) -> wp.fabricarray:
+        """The fabricarray of omni:fabric:worldMatrix."""
+        return self._view._fabric_world_matrices
+
+    @property
+    def view_to_fabric(self) -> wp.array:
+        """View-index to Fabric-index mapping."""
+        return self._view._view_to_fabric
+
+    @property
+    def count(self) -> int:
+        """Number of prims in the view."""
+        return self._view.count