update USD

python/rainbow/util/USD.py

@@ -65,6 +65,30 @@ def set_mesh_positions(self, name: str, V: ArrayLike, time: float) -> None:
             raise ValueError(f'Mesh {name} does not exist')
         vertex_positions = Vt.Vec3fArray(V.tolist())
         self.meshes[name].GetPointsAttr().Set(vertex_positions, time)
+
+    def get_mesh_positions(self, name: str, time: float) -> ArrayLike:
+        """ Retrieve the positions of a mesh at a given timestamp.
+
+        Args:
+            name (str): The name of the mesh.
+            time (float): The timestamp at which the positions should be retrieved.
+
+        Returns:
+            ArrayLike: An array containing the vertex positions of the mesh.
+
+        Raises:
+            ValueError: If the mesh does not exist in the scene, or if the mesh does not have positions set at the given timestamp.
+        """
+        if name not in self.meshes:
+            raise ValueError(f'Mesh {name} does not exist')
+
+        vertex_positions_attr = self.meshes[name].GetPointsAttr()
+        vertex_positions = vertex_positions_attr.Get(time)
+
+        if vertex_positions:
+            return np.array(vertex_positions, dtype=np.float64)
+        else:
+            raise ValueError(f"No positions set for mesh {name} at time {time}")
 
     def set_animation_time(self, duration: float) -> None:
         """ Set the total animation time of the scene

python/unit_tests/test_utils_USD.py

@@ -32,10 +32,12 @@ def test_set_mesh_positions(self):
         self.usd_instance.add_mesh(
             self.sample_mesh_name, self.sample_vertex_positions, self.sample_triangle_faces)
         new_positions = np.array(
-            [[0.1, 0.1, 0.1], [1.1, 0.1, 0.1], [0.1, 1.1, 0.1]])
+            [[0.1, 0.1, 0.1], [1.1, 0.1, 0.1], [0.1, 1.1, 0.1]], dtype=np.float64)
         time_stamp = 1.0
         self.usd_instance.set_mesh_positions(
             self.sample_mesh_name, new_positions, time_stamp)
+        updated_positions = self.usd_instance.get_mesh_positions(self.sample_mesh_name, time_stamp)
+        self.assertTrue(np.allclose(new_positions, updated_positions, rtol=1e-5, atol=1e-10))
 
     def test_set_mesh_positions_with_invalid_name(self):
         """ Test if the mesh does not exist, an error will be raised.