Honor USD cone axis during trimesh conversion

source/isaaclab/changelog.d/sylvesterkaczmarek-cone-primitive-axis.rst

@@ -0,0 +1,4 @@
+Fixed
+^^^^^
+
+* Fixed USD cone primitive conversion ignoring the configured ``axis`` and returning X/Y cones aligned to Z.

source/isaaclab/isaaclab/utils/mesh.py

@@ -167,6 +167,14 @@ def _create_cone_trimesh(prim: Usd.Prim) -> trimesh.Trimesh:
     mesh = trimesh.creation.cone(radius=radius, height=height)
     # shift all vertices down by height/2 for usd / trimesh cone primitive definition discrepancy
     mesh.apply_translation((0.0, 0.0, -height / 2.0))
+    axis = prim.GetAttribute("axis").Get()
+    if axis == "X":
+        # USD cones point their apex along the positive configured axis.
+        R = trimesh.transformations.rotation_matrix(np.radians(90), [0, 1, 0])
+        mesh.apply_transform(R)
+    elif axis == "Y":
+        R = trimesh.transformations.rotation_matrix(np.radians(-90), [1, 0, 0])
+        mesh.apply_transform(R)
     return mesh
 
 

source/isaaclab/test/utils/test_mesh_cone_axis.py

@@ -0,0 +1,47 @@
+# Copyright (c) 2022-2026, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import numpy as np
+import pytest
+
+from isaaclab.utils.mesh import create_trimesh_from_geom_shape
+
+pytestmark = pytest.mark.unit
+
+
+class _Attribute:
+    def __init__(self, value):
+        self._value = value
+
+    def Get(self):
+        return self._value
+
+
+class _ConePrim:
+    def __init__(self, axis: str, radius: float = 1.0, height: float = 4.0):
+        self._attributes = {"axis": axis, "radius": radius, "height": height}
+
+    def GetTypeName(self):
+        return "Cone"
+
+    def GetAttribute(self, name):
+        return _Attribute(self._attributes[name])
+
+    def GetPath(self):
+        return "/World/Cone"
+
+
+@pytest.mark.parametrize(("axis", "axis_index"), [("X", 0), ("Y", 1), ("Z", 2)])
+def test_cone_primitive_respects_axis_and_apex_direction(axis, axis_index):
+    height = 4.0
+    mesh = create_trimesh_from_geom_shape(_ConePrim(axis=axis, height=height))
+
+    vertices = np.asarray(mesh.vertices)
+    apex = vertices[np.argmax(vertices[:, axis_index])]
+    transverse_indices = [index for index in range(3) if index != axis_index]
+
+    assert np.isclose(apex[axis_index], height / 2.0)
+    np.testing.assert_allclose(apex[transverse_indices], 0.0, atol=1e-7)
+    assert np.isclose(vertices[:, axis_index].min(), -height / 2.0)