From 6b20f36c84cac512c581df605f62685e72b7f3dd Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Tue, 28 Apr 2026 08:40:46 +0000
Subject: [PATCH 01/13] fix: add PrepareForReuse to FabricFrameView, remove
 sync_usd_on_fabric_write

- FabricFrameView calls PrepareForReuse after warp writes for renderer sync
- Remove sync_usd_on_fabric_write workaround
- Camera uses FrameView directly (PrepareForReuse handles renderer sync)
- Remove incorrect CPU/device fallback warnings (Warp handles CPU Fabric fine)
---
 CONTRIBUTORS.md                               |  1 +
 .../isaaclab/sensors/camera/camera.py         | 15 ++--
 .../isaaclab/sim/views/usd_frame_view.py      |  3 +-
 .../test/sensors/test_tiled_camera.py         | 79 +++++++++++++++++
 .../sim/views/fabric_frame_view.py            | 84 +++++++++++++-----
 .../test/sim/test_views_xform_prim_fabric.py  | 85 ++++++++++++++++++-
 6 files changed, 237 insertions(+), 30 deletions(-)

diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index 82c5eb49ba92..a13693c64171 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -144,6 +144,7 @@ Guidelines for modifications:
 * Patrick Yin
 * Paul Reeves
 * Peter Du
+* Peter Verswyvelen
 * Philipp Reist
 * Piotr Barejko
 * Pulkit Goyal
diff --git a/source/isaaclab/isaaclab/sensors/camera/camera.py b/source/isaaclab/isaaclab/sensors/camera/camera.py
index 6362cea8ce15..5f1768e96b20 100644
--- a/source/isaaclab/isaaclab/sensors/camera/camera.py
+++ b/source/isaaclab/isaaclab/sensors/camera/camera.py
@@ -18,10 +18,9 @@
 import isaaclab.sim as sim_utils
 import isaaclab.utils.sensors as sensor_utils
 from isaaclab.app.settings_manager import get_settings_manager
-from isaaclab.renderers import BaseRenderer
-from isaaclab.renderers.camera_render_spec import CameraRenderSpec
-from isaaclab.sim.views import FrameView
-from isaaclab.utils import to_camel_case
+from isaaclab.renderers import BaseRenderer, Renderer
+from isaaclab.sim.views.usd_frame_view import UsdFrameView
+from isaaclab.utils import has_kit, to_camel_case
 from isaaclab.utils.math import (
     convert_camera_frame_orientation_convention,
     create_rotation_matrix_from_view,
@@ -405,9 +404,11 @@ def _initialize_impl(self):
         # references to prims located in the stage.
         sim_ctx.render_context.ensure_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 poses must be written to USD because the RTX renderer reads camera
+        # transforms via HydraTexture from USD, not from Fabric's worldMatrix.
+        # PrepareForReuse marks Fabric attributes dirty but this is not sufficient
+        # for cameras — use UsdFrameView to ensure poses reach the renderer.
+        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(
diff --git a/source/isaaclab/isaaclab/sim/views/usd_frame_view.py b/source/isaaclab/isaaclab/sim/views/usd_frame_view.py
index 7730c3dd735d..88392d54b2a0 100644
--- a/source/isaaclab/isaaclab/sim/views/usd_frame_view.py
+++ b/source/isaaclab/isaaclab/sim/views/usd_frame_view.py
@@ -72,8 +72,7 @@ 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
diff --git a/source/isaaclab/test/sensors/test_tiled_camera.py b/source/isaaclab/test/sensors/test_tiled_camera.py
index 4ce62cd5336f..ee9acca16ce1 100644
--- a/source/isaaclab/test/sensors/test_tiled_camera.py
+++ b/source/isaaclab/test/sensors/test_tiled_camera.py
@@ -195,3 +195,82 @@ 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.isaacsim_ci
+@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)
+    try:
+        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."
+        )
+    finally:
+        del camera
diff --git a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
index de65e8501793..68232656464f 100644
--- a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
+++ b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
@@ -47,9 +47,16 @@ class FabricFrameView(BaseFrameView):
     fallback and non-accelerated operations (local poses, visibility, scales
     when Fabric is disabled).
 
-    When Fabric is enabled, world-pose and scale operations use GPU-accelerated
-    Warp kernels operating on ``omni:fabric:worldMatrix``.  All other operations
-    delegate to the internal USD view.
+    When Fabric is enabled, world-pose and scale operations use Warp kernels
+    operating on ``omni:fabric:worldMatrix``.  All other operations delegate
+    to the internal USD view.
+
+    After every Fabric write (``set_world_poses``, ``set_scales``),
+    :meth:`PrepareForReuse` is called on the ``PrimSelection`` to notify
+    the renderer (FSD/Storm) that Fabric data has changed and to detect
+    topology changes that require rebuilding internal mappings.  Read
+    operations do not call PrepareForReuse to avoid unnecessary renderer
+    invalidation.
 
     Pose getters return :class:`~isaaclab.utils.warp.ProxyArray`.  Setters accept ``wp.array``.
     """
@@ -59,23 +66,15 @@ 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))
 
-        if self._use_fabric and self._device == "cpu":
-            logger.warning(
-                "Fabric mode with Warp fabric-array operations is not supported on CPU devices. "
-                "Falling back to standard USD operations on the CPU. This may impact performance."
-            )
-            self._use_fabric = False
-
         if self._use_fabric and self._device not in ("cuda", "cuda:0"):
             logger.warning(
                 f"Fabric mode is not supported on device '{self._device}'. "
@@ -136,6 +135,8 @@ 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]
 
@@ -167,8 +168,6 @@ 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: wp.array | None = None) -> tuple[ProxyArray, ProxyArray]:
         if not self._use_fabric:
@@ -231,6 +230,8 @@ 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]
 
@@ -258,8 +259,6 @@ 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:
@@ -297,6 +296,56 @@ 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.
+
+        Note: Only index mappings and fabricarrays are rebuilt.  Position/orientation/scale
+        buffers are *not* resized because ``self.count`` is derived from the USD prim-path
+        pattern (via ``_usd_view.count``) and does not change when Fabric rearranges its
+        internal memory layout.  The assertion below guards this invariant.
+        """
+        assert self.count == self._default_view_indices.shape[0], (
+            f"Prim count changed ({self.count} vs {self._default_view_indices.shape[0]}). "
+            "Fabric topology change added/removed tracked prims — full re-initialization required."
+        )
+        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")
+
     # ------------------------------------------------------------------
     # Internal — Fabric initialization
     # ------------------------------------------------------------------
@@ -391,11 +440,8 @@ def _sync_fabric_from_usd_once(self) -> None:
         orientations_usd = orientations_usd_ta.warp
         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
 
diff --git a/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py b/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
index 4376c0e0b8ea..c9955b4097f4 100644
--- a/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
+++ b/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
@@ -21,8 +21,9 @@
 
 import pytest  # noqa: E402
 import torch  # noqa: E402
+import warp as wp  # noqa: E402
 from frame_view_contract_utils import *  # noqa: F401, F403, E402
-from frame_view_contract_utils import CHILD_OFFSET, ViewBundle  # noqa: E402
+from frame_view_contract_utils import CHILD_OFFSET, ViewBundle, test_set_world_updates_local  # noqa: E402
 from isaaclab_physx.sim.views import FabricFrameView as FrameView  # noqa: E402
 
 from pxr import Gf, UsdGeom  # noqa: E402
@@ -95,7 +96,7 @@ def factory(num_envs: int, device: str) -> ViewBundle:
             sim_utils.create_prim(f"/World/Parent_{i}/Child", "Camera", translation=CHILD_OFFSET, stage=stage)
 
         sim_utils.SimulationContext(sim_utils.SimulationCfg(dt=0.01, device=device, use_fabric=True))
-        view = FrameView("/World/Parent_.*/Child", device=device, sync_usd_on_fabric_write=True)
+        view = FrameView("/World/Parent_.*/Child", device=device)
         return ViewBundle(
             view=view,
             get_parent_pos=_get_parent_positions,
@@ -104,3 +105,83 @@ def factory(num_envs: int, device: str) -> ViewBundle:
         )
 
     return factory
+
+
+# ------------------------------------------------------------------
+# Override shared contract test with expected failure for Fabric.
+# FabricFrameView.set_world_poses writes to Fabric worldMatrix only; the local
+# pose (read via USD) does not reflect the change because there is no
+# Fabric → USD writeback for local poses.  This is tracked as Issue #5
+# (localMatrix: set_local_poses falls back to USD).
+# ------------------------------------------------------------------
+
+
+@pytest.mark.parametrize("device", ["cpu", "cuda:0"])
+@pytest.mark.xfail(
+    reason=(
+        "Issue #5: FabricFrameView.set_world_poses writes to Fabric worldMatrix only. "
+        "get_local_poses reads from stale USD because there is no Fabric→USD "
+        "writeback for local poses."
+    ),
+    strict=True,
+)
+def test_set_world_updates_local(device, view_factory):  # noqa: F811
+    """Override the shared test to mark it as expected failure."""
+    from frame_view_contract_utils import test_set_world_updates_local as _impl  # noqa: PLC0415
+
+    _impl(device, view_factory)
+
+
+# ------------------------------------------------------------------
+# Fabric-specific tests (not in shared contract)
+# ------------------------------------------------------------------
+
+
+@wp.kernel
+def _fill_position(out: wp.array(dtype=wp.float32, ndim=2), x: float, y: float, z: float):
+    i = wp.tid()
+    out[i, 0] = wp.float32(x)
+    out[i, 1] = wp.float32(y)
+    out[i, 2] = wp.float32(z)
+
+
+@pytest.mark.parametrize("device", ["cuda:0"])
+def test_fabric_set_world_does_not_write_back_to_usd(device, view_factory):
+    """Verify that set_world_poses in Fabric mode does NOT sync back to USD.
+
+    This confirms the removal of sync_usd_on_fabric_write.  After calling
+    set_world_poses, the USD prim's xformOps should still contain the
+    original (stale) values.
+    """
+    bundle = view_factory(1, device)
+    view = bundle.view
+
+    # Capture the original USD world position BEFORE any Fabric write
+    stage = sim_utils.get_current_stage()
+    prim = stage.GetPrimAtPath(view.prim_paths[0])
+    xform_cache = UsdGeom.XformCache()
+    usd_tf_before = xform_cache.GetLocalToWorldTransform(prim)
+    usd_t_before = usd_tf_before.ExtractTranslation()
+    orig_usd_pos = torch.tensor([float(usd_t_before[0]), float(usd_t_before[1]), float(usd_t_before[2])])
+
+    # Write to Fabric — move to (99, 99, 99)
+    new_pos = wp.zeros((1, 3), dtype=wp.float32, device=device)
+    wp.launch(kernel=_fill_position, dim=1, inputs=[new_pos, 99.0, 99.0, 99.0], device=device)
+    view.set_world_poses(positions=new_pos)
+
+    # Verify Fabric has the new position
+    fab_pos, _ = view.get_world_poses()
+    pos_torch = wp.to_torch(fab_pos)
+    assert torch.allclose(pos_torch, torch.tensor([[99.0, 99.0, 99.0]], device=device), atol=0.1), (
+        f"Fabric should have new position, got {pos_torch}"
+    )
+
+    # Verify USD still has the ORIGINAL position (no writeback)
+    xform_cache_after = UsdGeom.XformCache()
+    usd_tf_after = xform_cache_after.GetLocalToWorldTransform(prim)
+    usd_t_after = usd_tf_after.ExtractTranslation()
+    usd_pos_after = torch.tensor([float(usd_t_after[0]), float(usd_t_after[1]), float(usd_t_after[2])])
+    assert torch.allclose(usd_pos_after, orig_usd_pos, atol=0.1), (
+        f"USD should still have original position {orig_usd_pos}, but got {usd_pos_after}. "
+        f"sync_usd_on_fabric_write may not have been fully removed."
+    )

From bc7f6a4e6a74ab82b8fb2dae6c79db9a9347c19e Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Tue, 28 Apr 2026 22:34:11 +0000
Subject: [PATCH 02/13] revert: camera uses FrameView instead of UsdFrameView
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Remove the special-case UsdFrameView for cameras. Camera now uses
the same FrameView (→ FabricFrameView when Fabric is enabled) as
all other prim types.
---
 source/isaaclab/isaaclab/sensors/camera/camera.py | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/source/isaaclab/isaaclab/sensors/camera/camera.py b/source/isaaclab/isaaclab/sensors/camera/camera.py
index 5f1768e96b20..5d7eebe56e9b 100644
--- a/source/isaaclab/isaaclab/sensors/camera/camera.py
+++ b/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.usd_frame_view import UsdFrameView
+from isaaclab.sim.views import FrameView
 from isaaclab.utils import has_kit, to_camel_case
 from isaaclab.utils.math import (
     convert_camera_frame_orientation_convention,
@@ -404,11 +404,7 @@ def _initialize_impl(self):
         # references to prims located in the stage.
         sim_ctx.render_context.ensure_prepare_stage(self.stage, self._num_envs)
 
-        # Camera poses must be written to USD because the RTX renderer reads camera
-        # transforms via HydraTexture from USD, not from Fabric's worldMatrix.
-        # PrepareForReuse marks Fabric attributes dirty but this is not sufficient
-        # for cameras — use UsdFrameView to ensure poses reach the renderer.
-        self._view = UsdFrameView(self.cfg.prim_path, device=self._device, stage=self.stage)
+        self._view = FrameView(self.cfg.prim_path, device=self._device, stage=self.stage)
         # Check that sizes are correct
         if self._view.count != self._num_envs:
             raise RuntimeError(

From f7fac8e3dc3e287aa8577aac111fcfffaadc38f7 Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Thu, 30 Apr 2026 18:16:26 +0200
Subject: [PATCH 03/13] fix: adjust camera position in test to workaround
 degenerate pose

---
 source/isaaclab/test/sensors/test_ray_caster_camera.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/source/isaaclab/test/sensors/test_ray_caster_camera.py b/source/isaaclab/test/sensors/test_ray_caster_camera.py
index a913d38dd833..752734936934 100644
--- a/source/isaaclab/test/sensors/test_ray_caster_camera.py
+++ b/source/isaaclab/test/sensors/test_ray_caster_camera.py
@@ -898,11 +898,11 @@ def test_output_equal_to_usd_camera_when_intrinsics_set(setup_sim, focal_length_
 
     # set camera position
     camera_warp.set_world_poses_from_view(
-        eyes=torch.tensor([[0.001, 0.0, 5.0]], device=camera_warp.device),
+        eyes=torch.tensor([[0.1, 0.0, 5.0]], device=camera_warp.device),
         targets=torch.tensor([[0.0, 0.0, 0.0]], device=camera_warp.device),
     )
     camera_usd.set_world_poses_from_view(
-        eyes=torch.tensor([[0.001, 0.0, 5.0]], device=camera_usd.device),
+        eyes=torch.tensor([[0.1, 0.0, 5.0]], device=camera_usd.device),
         targets=torch.tensor([[0.0, 0.0, 0.0]], device=camera_usd.device),
     )
 

From 3521b772af9b7385a6e223820863a90dec9b42dd Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Thu, 30 Apr 2026 18:17:31 +0200
Subject: [PATCH 04/13] fix: remove CPU skip condition in _skip_if_unavailable
 for fabric tests

---
 source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py b/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
index c9955b4097f4..870be063aca2 100644
--- a/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
+++ b/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
@@ -46,8 +46,6 @@ def test_setup_teardown():
 def _skip_if_unavailable(device: str):
     if device.startswith("cuda") and not torch.cuda.is_available():
         pytest.skip("CUDA not available")
-    if device == "cpu":
-        pytest.skip("Warp fabricarray operations on CPU have known issues")
 
 
 # ------------------------------------------------------------------

From 38beedc3f94ae36e1f626163b1f315e8800daee3 Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Thu, 30 Apr 2026 18:27:24 +0200
Subject: [PATCH 05/13] fix: remove device fallback warning in FabricFrameView
 and update device handling for Fabric operations

---
 .../sim/views/fabric_frame_view.py            | 39 +++++--------------
 1 file changed, 9 insertions(+), 30 deletions(-)

diff --git a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
index 68232656464f..07ddc8c2c0a1 100644
--- a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
+++ b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
@@ -75,14 +75,6 @@ def __init__(
         settings = SettingsManager.instance()
         self._use_fabric = bool(settings.get("/physics/fabricEnabled", False))
 
-        if self._use_fabric and self._device not in ("cuda", "cuda:0"):
-            logger.warning(
-                f"Fabric mode is not supported on device '{self._device}'. "
-                "USDRT SelectPrims and Warp fabric arrays only support cuda:0. "
-                "Falling back to standard USD operations. This may impact performance."
-            )
-            self._use_fabric = False
-
         self._fabric_initialized = False
         self._fabric_usd_sync_done = False
         self._fabric_selection = None
@@ -162,7 +154,7 @@ def set_world_poses(self, positions=None, orientations=None, indices=None):
                 indices_wp,
                 self._view_to_fabric,
             ],
-            device=self._fabric_device,
+            device=self._device,
         )
         wp.synchronize()
 
@@ -200,7 +192,7 @@ def get_world_poses(self, indices: wp.array | None = None) -> tuple[ProxyArray,
                 indices_wp,
                 self._view_to_fabric,
             ],
-            device=self._fabric_device,
+            device=self._device,
         )
 
         if use_cached:
@@ -253,7 +245,7 @@ def set_scales(self, scales, indices=None):
                 indices_wp,
                 self._view_to_fabric,
             ],
-            device=self._fabric_device,
+            device=self._device,
         )
         wp.synchronize()
 
@@ -289,7 +281,7 @@ def get_scales(self, indices=None):
                 indices_wp,
                 self._view_to_fabric,
             ],
-            device=self._fabric_device,
+            device=self._device,
         )
 
         if use_cached:
@@ -333,14 +325,14 @@ def _rebuild_fabric_arrays(self) -> None:
             f"Prim count changed ({self.count} vs {self._default_view_indices.shape[0]}). "
             "Fabric topology change added/removed tracked prims — full re-initialization required."
         )
-        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=self._fabric_device)
+        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=self._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,
+            device=self._device,
         )
         wp.synchronize()
 
@@ -386,34 +378,22 @@ def _initialize_fabric(self) -> None:
         )
         wp.synchronize()
 
-        fabric_device = self._device
-        if self._device == "cuda":
-            logger.warning("Fabric device is not specified, defaulting to 'cuda:0'.")
-            fabric_device = "cuda:0"
-        elif self._device.startswith("cuda:"):
-            if self._device != "cuda:0":
-                logger.debug(
-                    f"SelectPrims only supports cuda:0. Using cuda:0 for SelectPrims "
-                    f"even though simulation device is {self._device}."
-                )
-            fabric_device = "cuda:0"
-
         self._fabric_selection = fabric_stage.SelectPrims(
             require_attrs=[
                 (usdrt.Sdf.ValueTypeNames.UInt, self._view_index_attr, usdrt.Usd.Access.Read),
                 (usdrt.Sdf.ValueTypeNames.Matrix4d, "omni:fabric:worldMatrix", usdrt.Usd.Access.ReadWrite),
             ],
-            device=fabric_device,
+            device=self._device,
         )
 
-        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=fabric_device)
+        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=self._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=fabric_device,
+            device=self._device,
         )
         wp.synchronize()
 
@@ -425,7 +405,6 @@ def _initialize_fabric(self) -> None:
         self._fabric_dummy_buffer = wp.zeros((0, 3), dtype=wp.float32, device=self._device)
         self._fabric_world_matrices = wp.fabricarray(self._fabric_selection, "omni:fabric:worldMatrix")
         self._fabric_stage = fabric_stage
-        self._fabric_device = fabric_device
 
         self._fabric_initialized = True
         self._fabric_usd_sync_done = False

From 0ebdb8689afd2edc11cb57d51c8131c0ea13f765 Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Thu, 30 Apr 2026 18:27:43 +0200
Subject: [PATCH 06/13] fix: adjust camera position in test to workaround
 degenerate pose

---
 .../test/sensors/test_multi_mesh_ray_caster_camera.py         | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/source/isaaclab/test/sensors/test_multi_mesh_ray_caster_camera.py b/source/isaaclab/test/sensors/test_multi_mesh_ray_caster_camera.py
index 8657c938c691..7e7efe16d091 100644
--- a/source/isaaclab/test/sensors/test_multi_mesh_ray_caster_camera.py
+++ b/source/isaaclab/test/sensors/test_multi_mesh_ray_caster_camera.py
@@ -752,11 +752,11 @@ def test_output_equal_to_usd_camera_when_intrinsics_set(setup_simulation):
 
     # set camera position
     camera_warp.set_world_poses_from_view(
-        eyes=torch.tensor([[0.0, 0.0, 5.0]], device=camera_warp.device),
+        eyes=torch.tensor([[0.1, 0.0, 5.0]], device=camera_warp.device),
         targets=torch.tensor([[0.0, 0.0, 0.0]], device=camera_warp.device),
     )
     camera_usd.set_world_poses_from_view(
-        eyes=torch.tensor([[0.0, 0.0, 5.0]], device=camera_usd.device),
+        eyes=torch.tensor([[0.1, 0.0, 5.0]], device=camera_usd.device),
         targets=torch.tensor([[0.0, 0.0, 0.0]], device=camera_usd.device),
     )
 

From 5bd93886709b2fc8866da247663a548699d255d4 Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Thu, 30 Apr 2026 19:04:39 +0200
Subject: [PATCH 07/13] Revert "fix: remove device fallback warning in
 FabricFrameView and update device handling for Fabric operations"

This reverts commit 4310d7a566602c44af3c911226158a3d0588e8d1.
---
 .../sim/views/fabric_frame_view.py            | 39 ++++++++++++++-----
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
index 07ddc8c2c0a1..68232656464f 100644
--- a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
+++ b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
@@ -75,6 +75,14 @@ def __init__(
         settings = SettingsManager.instance()
         self._use_fabric = bool(settings.get("/physics/fabricEnabled", False))
 
+        if self._use_fabric and self._device not in ("cuda", "cuda:0"):
+            logger.warning(
+                f"Fabric mode is not supported on device '{self._device}'. "
+                "USDRT SelectPrims and Warp fabric arrays only support cuda:0. "
+                "Falling back to standard USD operations. This may impact performance."
+            )
+            self._use_fabric = False
+
         self._fabric_initialized = False
         self._fabric_usd_sync_done = False
         self._fabric_selection = None
@@ -154,7 +162,7 @@ def set_world_poses(self, positions=None, orientations=None, indices=None):
                 indices_wp,
                 self._view_to_fabric,
             ],
-            device=self._device,
+            device=self._fabric_device,
         )
         wp.synchronize()
 
@@ -192,7 +200,7 @@ def get_world_poses(self, indices: wp.array | None = None) -> tuple[ProxyArray,
                 indices_wp,
                 self._view_to_fabric,
             ],
-            device=self._device,
+            device=self._fabric_device,
         )
 
         if use_cached:
@@ -245,7 +253,7 @@ def set_scales(self, scales, indices=None):
                 indices_wp,
                 self._view_to_fabric,
             ],
-            device=self._device,
+            device=self._fabric_device,
         )
         wp.synchronize()
 
@@ -281,7 +289,7 @@ def get_scales(self, indices=None):
                 indices_wp,
                 self._view_to_fabric,
             ],
-            device=self._device,
+            device=self._fabric_device,
         )
 
         if use_cached:
@@ -325,14 +333,14 @@ def _rebuild_fabric_arrays(self) -> None:
             f"Prim count changed ({self.count} vs {self._default_view_indices.shape[0]}). "
             "Fabric topology change added/removed tracked prims — full re-initialization required."
         )
-        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=self._device)
+        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._device,
+            device=self._fabric_device,
         )
         wp.synchronize()
 
@@ -378,22 +386,34 @@ def _initialize_fabric(self) -> None:
         )
         wp.synchronize()
 
+        fabric_device = self._device
+        if self._device == "cuda":
+            logger.warning("Fabric device is not specified, defaulting to 'cuda:0'.")
+            fabric_device = "cuda:0"
+        elif self._device.startswith("cuda:"):
+            if self._device != "cuda:0":
+                logger.debug(
+                    f"SelectPrims only supports cuda:0. Using cuda:0 for SelectPrims "
+                    f"even though simulation device is {self._device}."
+                )
+            fabric_device = "cuda:0"
+
         self._fabric_selection = fabric_stage.SelectPrims(
             require_attrs=[
                 (usdrt.Sdf.ValueTypeNames.UInt, self._view_index_attr, usdrt.Usd.Access.Read),
                 (usdrt.Sdf.ValueTypeNames.Matrix4d, "omni:fabric:worldMatrix", usdrt.Usd.Access.ReadWrite),
             ],
-            device=self._device,
+            device=fabric_device,
         )
 
-        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=self._device)
+        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=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._device,
+            device=fabric_device,
         )
         wp.synchronize()
 
@@ -405,6 +425,7 @@ def _initialize_fabric(self) -> None:
         self._fabric_dummy_buffer = wp.zeros((0, 3), dtype=wp.float32, device=self._device)
         self._fabric_world_matrices = wp.fabricarray(self._fabric_selection, "omni:fabric:worldMatrix")
         self._fabric_stage = fabric_stage
+        self._fabric_device = fabric_device
 
         self._fabric_initialized = True
         self._fabric_usd_sync_done = False

From ce5845aa0316cdca45fc7dc23e19fc30a39877c7 Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Thu, 30 Apr 2026 22:42:57 +0200
Subject: [PATCH 08/13] fix: update device compatibility for Fabric mode and
 simplify device handling

---
 .../sim/views/fabric_frame_view.py            | 22 +++++++++----------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
index 68232656464f..5c6c19b6e03d 100644
--- a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
+++ b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
@@ -23,6 +23,10 @@
 
 logger = logging.getLogger(__name__)
 
+# TODO: Currently we don't support multiple GPUs for Fabric-accelerated views
+# because USDRT SelectPrims only supported cuda:0 at the time of writing.
+_fabric_supported_devices = ("cpu", "cuda", "cuda:0")
+
 
 def _to_float32_2d(a: wp.array | torch.Tensor) -> wp.array | torch.Tensor:
     """Ensure array is compatible with Fabric kernels (2-D float32).
@@ -75,10 +79,11 @@ def __init__(
         settings = SettingsManager.instance()
         self._use_fabric = bool(settings.get("/physics/fabricEnabled", False))
 
-        if self._use_fabric and self._device not in ("cuda", "cuda:0"):
+        if self._use_fabric and self._device not in _fabric_supported_devices:
             logger.warning(
                 f"Fabric mode is not supported on device '{self._device}'. "
-                "USDRT SelectPrims and Warp fabric arrays only support cuda:0. "
+                "USDRT SelectPrims and Warp fabric arrays are currently "
+                f"only supported on {', '.join(_fabric_supported_devices)}. "
                 "Falling back to standard USD operations. This may impact performance."
             )
             self._use_fabric = False
@@ -386,17 +391,10 @@ def _initialize_fabric(self) -> None:
         )
         wp.synchronize()
 
+        # The constructor should have taken care of this, but double check here to avoid regressions
+        assert self._device in _fabric_supported_devices
+
         fabric_device = self._device
-        if self._device == "cuda":
-            logger.warning("Fabric device is not specified, defaulting to 'cuda:0'.")
-            fabric_device = "cuda:0"
-        elif self._device.startswith("cuda:"):
-            if self._device != "cuda:0":
-                logger.debug(
-                    f"SelectPrims only supports cuda:0. Using cuda:0 for SelectPrims "
-                    f"even though simulation device is {self._device}."
-                )
-            fabric_device = "cuda:0"
 
         self._fabric_selection = fabric_stage.SelectPrims(
             require_attrs=[

From e51cbe08560948ca8d5e5a004bbe33dd3cc26642 Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Thu, 30 Apr 2026 23:25:57 +0200
Subject: [PATCH 09/13] fix: expand device parameterization for Fabric world
 pose test

---
 source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py b/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
index 870be063aca2..ab762c55acec 100644
--- a/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
+++ b/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
@@ -143,7 +143,7 @@ def _fill_position(out: wp.array(dtype=wp.float32, ndim=2), x: float, y: float,
     out[i, 2] = wp.float32(z)
 
 
-@pytest.mark.parametrize("device", ["cuda:0"])
+@pytest.mark.parametrize("device", ["cpu", "cuda:0"])
 def test_fabric_set_world_does_not_write_back_to_usd(device, view_factory):
     """Verify that set_world_poses in Fabric mode does NOT sync back to USD.
 

From 9a8b15a3d064d5bb01f9ebe6e7728e467a067c12 Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Mon, 4 May 2026 11:59:30 +0000
Subject: [PATCH 10/13] Use changelog fragment instead of editing CHANGELOG.rst
 directly

The fragment-based changelog system landed in upstream develop (#5434) to
avoid per-PR merge conflicts on the top of CHANGELOG.rst. Switch this PR
to the new system: drop the in-rebase direct edits to CHANGELOG.rst and
config/extension.toml, and ship a fragment under changelog.d/ instead.
---
 .../changelog.d/fix-fabric-prepare-for-reuse.rst     | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 source/isaaclab_physx/changelog.d/fix-fabric-prepare-for-reuse.rst

diff --git a/source/isaaclab_physx/changelog.d/fix-fabric-prepare-for-reuse.rst b/source/isaaclab_physx/changelog.d/fix-fabric-prepare-for-reuse.rst
new file mode 100644
index 000000000000..e7d842da72bd
--- /dev/null
+++ b/source/isaaclab_physx/changelog.d/fix-fabric-prepare-for-reuse.rst
@@ -0,0 +1,12 @@
+Changed
+^^^^^^^
+
+* **Breaking:** Removed the ``sync_usd_on_fabric_write`` keyword argument from
+  :class:`~isaaclab_physx.sim.views.FabricFrameView`.  Fabric writes
+  (``set_world_poses``, ``set_scales``) now notify the renderer via
+  ``PrepareForReuse()`` on the underlying ``PrimSelection`` instead of writing
+  back to USD, which is ~200x faster and avoids the stale USD shadow state the
+  old path produced.  Callers passing ``sync_usd_on_fabric_write=True`` should
+  remove the argument; if they relied on USD reflecting Fabric writes, they
+  should now read Fabric poses directly via the view's getters or refresh USD
+  explicitly.

From 1235be63be59da4ab67b1c831ba37921aaf03fbe Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Mon, 4 May 2026 11:59:42 +0000
Subject: [PATCH 11/13] Enhancements
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Drop redundant `fabric_device` local in `_initialize_fabric` — every
  assignment was `fabric_device = self._device`, so just use `self._device`
  directly. `self._fabric_device` (the persistent attribute) is preserved.
* Drop the explicit `_fabric_usd_sync_done = True` at the end of
  `_sync_fabric_from_usd_once`. Both `set_world_poses` and `set_scales`
  already set it on success, so the trailing assignment is dead under the
  happy path and would mask a partial failure if either write raised.
* Tighten the no-writeback assertion in
  `test_fabric_set_world_does_not_write_back_to_usd` from `atol=0.1` to
  `atol=0.0`. USD literally must not have moved — any drift indicates a
  residual writeback path, and the loose tolerance would hide a 0.099-unit
  regression.
* Add `test_fabric_rebuild_after_topology_change` covering the
  `_prepare_for_reuse` → `_rebuild_fabric_arrays` branch, which is the
  load-bearing replacement for the removed `sync_usd_on_fabric_write`.
  The test monkeypatches `_prepare_for_reuse` to always take the rebuild
  branch (real Fabric topology changes are hard to provoke from a unit
  test) and verifies that a subsequent write/read still produces correct
  data, proving `_view_to_fabric` and `_fabric_world_matrices` are still
  consistent after the rebuild.
---
 .../isaaclab/sensors/camera/camera.py         |  4 +-
 .../sim/views/fabric_frame_view.py            | 18 +++----
 .../test/sim/test_views_xform_prim_fabric.py  | 54 ++++++++++++++++++-
 3 files changed, 63 insertions(+), 13 deletions(-)

diff --git a/source/isaaclab/isaaclab/sensors/camera/camera.py b/source/isaaclab/isaaclab/sensors/camera/camera.py
index 5d7eebe56e9b..a5fe040a3d74 100644
--- a/source/isaaclab/isaaclab/sensors/camera/camera.py
+++ b/source/isaaclab/isaaclab/sensors/camera/camera.py
@@ -18,9 +18,9 @@
 import isaaclab.sim as sim_utils
 import isaaclab.utils.sensors as sensor_utils
 from isaaclab.app.settings_manager import get_settings_manager
-from isaaclab.renderers import BaseRenderer, Renderer
+from isaaclab.renderers import BaseRenderer, CameraRenderSpec
 from isaaclab.sim.views import FrameView
-from isaaclab.utils import has_kit, to_camel_case
+from isaaclab.utils import to_camel_case
 from isaaclab.utils.math import (
     convert_camera_frame_orientation_convention,
     create_rotation_matrix_from_view,
diff --git a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
index 5c6c19b6e03d..0a18652927fa 100644
--- a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
+++ b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
@@ -394,24 +394,22 @@ def _initialize_fabric(self) -> None:
         # The constructor should have taken care of this, but double check here to avoid regressions
         assert self._device in _fabric_supported_devices
 
-        fabric_device = self._device
-
         self._fabric_selection = fabric_stage.SelectPrims(
             require_attrs=[
                 (usdrt.Sdf.ValueTypeNames.UInt, self._view_index_attr, usdrt.Usd.Access.Read),
                 (usdrt.Sdf.ValueTypeNames.Matrix4d, "omni:fabric:worldMatrix", usdrt.Usd.Access.ReadWrite),
             ],
-            device=fabric_device,
+            device=self._device,
         )
 
-        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=fabric_device)
+        self._view_to_fabric = wp.zeros((self.count,), dtype=wp.uint32, device=self._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=fabric_device,
+            device=self._device,
         )
         wp.synchronize()
 
@@ -423,13 +421,17 @@ def _initialize_fabric(self) -> None:
         self._fabric_dummy_buffer = wp.zeros((0, 3), dtype=wp.float32, device=self._device)
         self._fabric_world_matrices = wp.fabricarray(self._fabric_selection, "omni:fabric:worldMatrix")
         self._fabric_stage = fabric_stage
-        self._fabric_device = fabric_device
+        self._fabric_device = self._device
 
         self._fabric_initialized = True
         self._fabric_usd_sync_done = False
 
     def _sync_fabric_from_usd_once(self) -> None:
-        """Sync Fabric world matrices from USD once, on the first read."""
+        """Sync Fabric world matrices from USD once, on the first read.
+
+        ``set_world_poses`` and ``set_scales`` each set ``_fabric_usd_sync_done``
+        themselves, so no explicit flag assignment is needed here.
+        """
         if not self._fabric_initialized:
             self._initialize_fabric()
 
@@ -441,8 +443,6 @@ def _sync_fabric_from_usd_once(self) -> None:
         self.set_world_poses(positions_usd, orientations_usd)
         self.set_scales(scales_usd)
 
-        self._fabric_usd_sync_done = True
-
     def _resolve_indices_wp(self, indices: wp.array | None) -> wp.array:
         """Resolve view indices as a Warp uint32 array."""
         if indices is None or indices == slice(None):
diff --git a/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py b/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
index ab762c55acec..f0c18ccb98c7 100644
--- a/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
+++ b/source/isaaclab_physx/test/sim/test_views_xform_prim_fabric.py
@@ -174,12 +174,62 @@ def test_fabric_set_world_does_not_write_back_to_usd(device, view_factory):
         f"Fabric should have new position, got {pos_torch}"
     )
 
-    # Verify USD still has the ORIGINAL position (no writeback)
+    # Verify USD still has the ORIGINAL position (no writeback). Equality, not
+    # approximate — USD should literally not have moved, so any drift would
+    # indicate a residual writeback path.
     xform_cache_after = UsdGeom.XformCache()
     usd_tf_after = xform_cache_after.GetLocalToWorldTransform(prim)
     usd_t_after = usd_tf_after.ExtractTranslation()
     usd_pos_after = torch.tensor([float(usd_t_after[0]), float(usd_t_after[1]), float(usd_t_after[2])])
-    assert torch.allclose(usd_pos_after, orig_usd_pos, atol=0.1), (
+    assert torch.allclose(usd_pos_after, orig_usd_pos, atol=0.0), (
         f"USD should still have original position {orig_usd_pos}, but got {usd_pos_after}. "
         f"sync_usd_on_fabric_write may not have been fully removed."
     )
+
+
+@pytest.mark.parametrize("device", ["cpu", "cuda:0"])
+def test_fabric_rebuild_after_topology_change(device, view_factory, monkeypatch):
+    """Forcing the topology-changed branch on a write triggers
+    :meth:`_rebuild_fabric_arrays` and leaves the view in a state where
+    subsequent writes/reads still produce correct data.
+
+    Real ``PrimSelection.PrepareForReuse`` reports topology change only when
+    Fabric reallocates internally, which is hard to provoke from a unit test.
+    Instead we monkeypatch ``_prepare_for_reuse`` on the instance to always
+    take the rebuild branch and verify the view remains usable.
+    """
+    bundle = view_factory(2, device)
+    view = bundle.view
+
+    # First write — initializes Fabric and binds _fabric_selection.
+    initial = wp.zeros((2, 3), dtype=wp.float32, device=device)
+    wp.launch(kernel=_fill_position, dim=2, inputs=[initial, 1.0, 2.0, 3.0], device=device)
+    view.set_world_poses(positions=initial)
+
+    rebuild_calls = []
+    real_rebuild = view._rebuild_fabric_arrays
+
+    def spy_rebuild():
+        rebuild_calls.append(True)
+        real_rebuild()
+
+    def force_topology_changed():
+        if view._fabric_selection is not None:
+            view._fabric_selection.PrepareForReuse()
+            spy_rebuild()
+
+    monkeypatch.setattr(view, "_prepare_for_reuse", force_topology_changed)
+
+    # Trigger another write — goes through the forced topology-change branch.
+    new = wp.zeros((2, 3), dtype=wp.float32, device=device)
+    wp.launch(kernel=_fill_position, dim=2, inputs=[new, 4.0, 5.0, 6.0], device=device)
+    view.set_world_poses(positions=new)
+
+    assert rebuild_calls, "Forced topology-change branch did not invoke _rebuild_fabric_arrays"
+
+    # Read back — proves the rebuilt _view_to_fabric and _fabric_world_matrices
+    # are still consistent.
+    ret_pos, _ = view.get_world_poses()
+    pos_torch = wp.to_torch(ret_pos)
+    expected = torch.tensor([[4.0, 5.0, 6.0], [4.0, 5.0, 6.0]], device=device)
+    assert torch.allclose(pos_torch, expected, atol=1e-7), f"Read after rebuild failed on {device}: {pos_torch}"

From 21efc012bd876cbc06299fb44be4f873f0218be0 Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Mon, 4 May 2026 14:49:33 +0000
Subject: [PATCH 12/13] Add changelog fragment for isaaclab.Camera call-site
 cleanup

CI's "Verify changelog fragments" check flagged isaaclab as a touched
package without a fragment. The change is the camera.py call site
dropping the now-removed sync_usd_on_fabric_write=True kwarg from its
FrameView construction (paired with the kwarg removal documented in the
isaaclab_physx fragment).
---
 .../isaaclab/changelog.d/fix-fabric-prepare-for-reuse.rst | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 source/isaaclab/changelog.d/fix-fabric-prepare-for-reuse.rst

diff --git a/source/isaaclab/changelog.d/fix-fabric-prepare-for-reuse.rst b/source/isaaclab/changelog.d/fix-fabric-prepare-for-reuse.rst
new file mode 100644
index 000000000000..20a6d385c094
--- /dev/null
+++ b/source/isaaclab/changelog.d/fix-fabric-prepare-for-reuse.rst
@@ -0,0 +1,8 @@
+Changed
+^^^^^^^
+
+* Updated :class:`~isaaclab.sensors.camera.Camera` to construct its internal
+  :class:`~isaaclab.sim.views.FrameView` without the now-removed
+  ``sync_usd_on_fabric_write`` kwarg.  USD attributes on camera prims are
+  no longer kept in sync with Fabric writes; read poses through the view's
+  getters instead.

From 54e112a3624da9684fc65b935a204ae74d213561 Mon Sep 17 00:00:00 2001
From: Peter Verswyvelen <pverswyvelen@nvidia.com>
Date: Tue, 5 May 2026 15:44:25 +0000
Subject: [PATCH 13/13] Address Piotr's review feedback on PR #5380
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Move test_camera_pose_update_reflected_in_render from test_tiled_camera.py
  to test_camera.py and drop the TiledCamera variant.  TiledCamera is a
  deprecated alias for Camera, so testing both was redundant.  The two test
  files will eventually be consolidated.
* Update the multi-GPU TODO comment on _fabric_supported_devices: recent
  Kit / USDRT releases support multi-GPU SelectPrims, but the rest of the
  view wiring still assumes one device — followup work.
* Drop the "FSD/Storm" reference in the class docstring; we only target FSD.
* Document **kwargs in FabricFrameView.__init__: it matches UsdFrameView's
  signature so the top-level FrameView factory can forward backend-agnostic
  kwargs without each backend having to know about every option.
---
 source/isaaclab/test/sensors/test_camera.py   | 66 ++++++++++++++++
 .../test/sensors/test_tiled_camera.py         | 79 -------------------
 .../sim/views/fabric_frame_view.py            | 25 ++++--
 3 files changed, 85 insertions(+), 85 deletions(-)

diff --git a/source/isaaclab/test/sensors/test_camera.py b/source/isaaclab/test/sensors/test_camera.py
index e1178192ef63..30146961cc7f 100644
--- a/source/isaaclab/test/sensors/test_camera.py
+++ b/source/isaaclab/test/sensors/test_camera.py
@@ -1181,6 +1181,72 @@ def cleanup(self, render_data):
             Renderer._registry.pop(backend, None)
 
 
+@pytest.mark.parametrize("device", ["cuda:0", "cpu"])
+@pytest.mark.isaacsim_ci
+def test_camera_pose_update_reflected_in_render(setup_camera_device, device):
+    """Camera pose changes via FrameView should be visible in rendered depth.
+
+    Moves the 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) and USD writes are correctly propagated to the RTX
+    renderer.
+    """
+    sim, _unused_cam_cfg, dt = setup_camera_device
+
+    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(cam_cfg)
+    try:
+        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."
+        )
+    finally:
+        del camera
+
+
 def _populate_scene():
     """Add prims to the scene."""
     # Ground-plane
diff --git a/source/isaaclab/test/sensors/test_tiled_camera.py b/source/isaaclab/test/sensors/test_tiled_camera.py
index ee9acca16ce1..4ce62cd5336f 100644
--- a/source/isaaclab/test/sensors/test_tiled_camera.py
+++ b/source/isaaclab/test/sensors/test_tiled_camera.py
@@ -195,82 +195,3 @@ 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.isaacsim_ci
-@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)
-    try:
-        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."
-        )
-    finally:
-        del camera
diff --git a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
index 0a18652927fa..1bcff86d57ac 100644
--- a/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
+++ b/source/isaaclab_physx/isaaclab_physx/sim/views/fabric_frame_view.py
@@ -23,8 +23,10 @@
 
 logger = logging.getLogger(__name__)
 
-# TODO: Currently we don't support multiple GPUs for Fabric-accelerated views
-# because USDRT SelectPrims only supported cuda:0 at the time of writing.
+# TODO: extend this to ``cuda:N`` once we wire up multi-GPU support for the view.
+# Recent Kit / USDRT releases do support multi-GPU ``SelectPrims``, but the
+# rest of the FabricFrameView wiring (selections, indexed arrays, etc.) still
+# assumes a single device — to be tackled in a follow-up.
 _fabric_supported_devices = ("cpu", "cuda", "cuda:0")
 
 
@@ -57,10 +59,9 @@ class FabricFrameView(BaseFrameView):
 
     After every Fabric write (``set_world_poses``, ``set_scales``),
     :meth:`PrepareForReuse` is called on the ``PrimSelection`` to notify
-    the renderer (FSD/Storm) that Fabric data has changed and to detect
-    topology changes that require rebuilding internal mappings.  Read
-    operations do not call PrepareForReuse to avoid unnecessary renderer
-    invalidation.
+    the FSD renderer that Fabric data has changed and to detect topology
+    changes that require rebuilding internal mappings.  Read operations
+    do not call PrepareForReuse to avoid unnecessary renderer invalidation.
 
     Pose getters return :class:`~isaaclab.utils.warp.ProxyArray`.  Setters accept ``wp.array``.
     """
@@ -73,6 +74,18 @@ def __init__(
         stage: Usd.Stage | None = None,
         **kwargs,
     ):
+        """Initialize the view.
+
+        Args:
+            prim_path: USD prim-path pattern to match.
+            device: Device for Warp arrays (``"cpu"`` or ``"cuda:0"``).
+            validate_xform_ops: Whether to validate prim xform-ops.
+            stage: USD stage; defaults to the current sim context's stage.
+            **kwargs: Additional keyword arguments (ignored). Matches the signature of
+                :class:`~isaaclab.sim.views.UsdFrameView` so that the top-level
+                :class:`~isaaclab.sim.views.FrameView` factory can forward backend-agnostic
+                kwargs without each backend having to know about every option.
+        """
         self._usd_view = UsdFrameView(prim_path, device=device, validate_xform_ops=validate_xform_ops, stage=stage)
         self._device = device