draft: import usd

embodichain/lab/sim/cfg.py

@@ -546,6 +546,14 @@ class RigidObjectCfg(ObjectBaseCfg):
     body_scale: Union[tuple, list] = (1.0, 1.0, 1.0)
     """Scale of the rigid body in the simulation world frame."""
 
+    use_usd_properties: bool = False
+    """Whether to use physical properties from USD file instead of config.
+
+    When True: Keep all physical properties (drive, physics attrs, etc.) from USD file.
+    When False (default): Override USD properties with config values (URDF behavior).
+    Only effective for USD files, ignored for URDF files.
+    """
+
     def to_dexsim_body_type(self) -> ActorType:
         """Convert the body type to dexsim ActorType."""
         if self.body_type == "dynamic":
@@ -1018,6 +1026,14 @@ class ArticulationCfg(ObjectBaseCfg):
     Currently, the uv mapping is computed for each link with projection uv mapping method.
     """
 
+    use_usd_properties: bool = False
+    """Whether to use physical properties from USD file instead of config.
+
+    When True: Keep all physical properties (drive, physics attrs, etc.) from USD file.
+    When False (default): Override USD properties with config values (URDF behavior).
+    Only effective for USD files, ignored for URDF files.
+    """
+
 
 @configclass
 class RobotCfg(ArticulationCfg):

embodichain/lab/sim/objects/articulation.py

@@ -582,41 +582,45 @@ def __init__(
         if self.cfg.init_qpos is None:
             self.cfg.init_qpos = torch.zeros(self.dof, dtype=torch.float32)
 
-        # Set articulation configuration in DexSim
-        set_dexsim_articulation_cfg(entities, self.cfg)
-
-        # Init joint drive parameters.
-        num_entities = len(entities)
-        dof = self._data.dof
-        default_cfg = JointDrivePropertiesCfg()
-        self.default_joint_damping = torch.full(
-            (num_entities, dof), default_cfg.damping, dtype=torch.float32, device=device
-        )
-        self.default_joint_stiffness = torch.full(
-            (num_entities, dof),
-            default_cfg.stiffness,
-            dtype=torch.float32,
-            device=device,
-        )
-        self.default_joint_max_effort = torch.full(
-            (num_entities, dof),
-            default_cfg.max_effort,
-            dtype=torch.float32,
-            device=device,
-        )
-        self.default_joint_max_velocity = torch.full(
-            (num_entities, dof),
-            default_cfg.max_velocity,
-            dtype=torch.float32,
-            device=device,
-        )
-        self.default_joint_friction = torch.full(
-            (num_entities, dof),
-            default_cfg.friction,
-            dtype=torch.float32,
-            device=device,
-        )
-        self._set_default_joint_drive()
+        if not cfg.use_usd_properties:
+            # Set articulation configuration in DexSim
+            set_dexsim_articulation_cfg(entities, self.cfg)
+
+            # Init joint drive parameters.
+            num_entities = len(entities)
+            dof = self._data.dof
+            default_cfg = JointDrivePropertiesCfg()
+            self.default_joint_damping = torch.full(
+                (num_entities, dof),
+                default_cfg.damping,
+                dtype=torch.float32,
+                device=device,
+            )
+            self.default_joint_stiffness = torch.full(
+                (num_entities, dof),
+                default_cfg.stiffness,
+                dtype=torch.float32,
+                device=device,
+            )
+            self.default_joint_max_effort = torch.full(
+                (num_entities, dof),
+                default_cfg.max_effort,
+                dtype=torch.float32,
+                device=device,
+            )
+            self.default_joint_max_velocity = torch.full(
+                (num_entities, dof),
+                default_cfg.max_velocity,
+                dtype=torch.float32,
+                device=device,
+            )
+            self.default_joint_friction = torch.full(
+                (num_entities, dof),
+                default_cfg.friction,
+                dtype=torch.float32,
+                device=device,
+            )
+            self._set_default_joint_drive()
 
         self.pk_chain = None
         if self.cfg.build_pk_chain:

embodichain/lab/sim/objects/rigid_object.py

@@ -211,9 +211,10 @@ def __init__(
         self._visual_material: List[VisualMaterialInst] = [None] * len(entities)
         self.is_shared_visual_material = False
 
-        for entity in entities:
-            entity.set_body_scale(*cfg.body_scale)
-            entity.set_physical_attr(cfg.attrs.attr())
+        if not cfg.use_usd_properties:
+            for entity in entities:
+                entity.set_body_scale(*cfg.body_scale)
+                entity.set_physical_attr(cfg.attrs.attr())
 
         if device.type == "cuda":
             self._world.update(0.001)

embodichain/lab/sim/sim_manager.py

@@ -1030,9 +1030,31 @@ def add_articulation(
         env_list = [self._env] if len(self._arenas) == 0 else self._arenas
         obj_list = []
 
-        for env in env_list:
-            art = env.load_urdf(cfg.fpath)
-            obj_list.append(art)
+        is_usd = cfg.fpath.endswith((".usd", ".usda", ".usdc"))
+        if is_usd:
+            # TODO: currently not supporting multiple arenas for USD
+            env = self._env
+            results = env.import_from_usd_file(cfg.fpath, return_object=True)
+            print("USD import results:", results)
+
+            articulations_found = []
+            for key, value in results.items():
+                if isinstance(value, dexsim.engine.Articulation):
+                    articulations_found.append(value)
+
+            if len(articulations_found) == 0:
+                logger.log_error(f"No articulation found in USD file {cfg.fpath}.")
+                return None
+            elif len(articulations_found) > 1:
+                logger.log_error(
+                    f"Multiple articulations found in USD file {cfg.fpath}. "
+                )
+            elif len(articulations_found) == 1:
+                obj_list.append(articulations_found[0])
+        else:
+            for env in env_list:
+                art = env.load_urdf(cfg.fpath)
+                obj_list.append(art)
 
         articulation = Articulation(cfg=cfg, entities=obj_list, device=self.device)
 
@@ -1092,9 +1114,31 @@ def add_robot(self, cfg: RobotCfg) -> Robot | None:
         env_list = [self._env] if len(self._arenas) == 0 else self._arenas
         obj_list = []
 
-        for env in env_list:
-            art = env.load_urdf(cfg.fpath)
-            obj_list.append(art)
+        is_usd = cfg.fpath.endswith((".usd", ".usda", ".usdc"))
+        if is_usd:
+            # TODO: currently not supporting multiple arenas for USD
+            env = self._env
+            results = env.import_from_usd_file(cfg.fpath, return_object=True)
+            print("USD import results:", results)
+
+            articulations_found = []
+            for key, value in results.items():
+                if isinstance(value, dexsim.engine.Articulation):
+                    articulations_found.append(value)
+
+            if len(articulations_found) == 0:
+                logger.log_error(f"No articulation found in USD file {cfg.fpath}.")
+                return None
+            elif len(articulations_found) > 1:
+                logger.log_error(
+                    f"Multiple articulations found in USD file {cfg.fpath}. "
+                )
+            elif len(articulations_found) == 1:
+                obj_list.append(articulations_found[0])
+        else:
+            for env in env_list:
+                art = env.load_urdf(cfg.fpath)
+                obj_list.append(art)
 
         robot = Robot(cfg=cfg, entities=obj_list, device=self.device)
 

embodichain/lab/sim/utility/sim_utils.py

@@ -219,6 +219,28 @@ def load_mesh_objects_from_cfg(
 
         compute_uv = cfg.shape.compute_uv
 
+        is_usd = fpath.endswith((".usd", ".usda", ".usdc"))
+        if is_usd:
+            # TODO: currently not supporting multiple arenas for USD
+            _env: dexsim.environment.Env = dexsim.default_world().get_env()
+            results = _env.import_from_usd_file(fpath, return_object=True)
+            print(f"import usd result: {results}")
+
+            rigidbodys_found = []
+            for key, value in results.items():
+                if isinstance(value, dexsim.cuda.pybind.models.MeshObject):
+                    rigidbodys_found.append(value)
+            if len(rigidbodys_found) == 0:
+                logger.log_error(f"No rigid body found in USD file: {fpath}")
+            elif len(rigidbodys_found) > 1:
+                logger.log_error(f"Multiple rigid bodies found in USD file: {fpath}.")
+            elif len(rigidbodys_found) == 1:
+                obj_list.append(rigidbodys_found[0])
+                return obj_list
+        else:
+            # non-usd file does not support this option, will be ignored if set.
+            cfg.use_usd_properties = False
+
         for i, env in enumerate(env_list):
             if max_convex_hull_num > 1:
                 obj = env.load_actor_with_coacd(

scripts/tutorials/sim/import_usd.py

@@ -0,0 +1,168 @@
+# ----------------------------------------------------------------------------
+# Copyright (c) 2021-2025 DexForce Technology Co., Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ----------------------------------------------------------------------------
+
+"""
+This script demonstrates how to create a simulation scene using SimulationManager.
+It shows the basic setup of simulation context, adding objects, and sensors.
+"""
+
+import argparse
+import time
+
+from embodichain.lab.sim import SimulationManager, SimulationManagerCfg
+from embodichain.lab.sim.cfg import RigidBodyAttributesCfg
+from embodichain.lab.sim.shapes import CubeCfg, MeshCfg
+from embodichain.lab.sim.objects import (
+    RigidObject,
+    RigidObjectCfg,
+    ArticulationCfg,
+    Articulation,
+)
+from dexsim.utility.path import get_resources_data_path
+
+
+def main():
+    """Main function to create and run the simulation scene."""
+
+    # Parse command line arguments
+    parser = argparse.ArgumentParser(
+        description="Create a simulation scene with SimulationManager"
+    )
+    parser.add_argument(
+        "--headless",
+        action="store_true",
+        default=False,
+        help="Run simulation in headless mode",
+    )
+    parser.add_argument(
+        "--device", type=str, default="cpu", help="Simulation device (cuda or cpu)"
+    )
+    parser.add_argument(
+        "--enable_rt",
+        action="store_true",
+        default=True,
+        help="Enable ray tracing for better visuals",
+    )
+    args = parser.parse_args()
+
+    # Configure the simulation
+    sim_cfg = SimulationManagerCfg(
+        width=1920,
+        height=1080,
+        headless=True,
+        physics_dt=1.0 / 100.0,  # Physics timestep (100 Hz)
+        sim_device=args.device,
+        enable_rt=args.enable_rt,  # Enable ray tracing for better visuals
+        num_envs=1,
+        arena_space=3.0,
+    )
+
+    # Create the simulation instance
+    sim = SimulationManager(sim_cfg)
+    # Open window when the scene has been set up
+    if not args.headless:
+        sim.open_window()
+
+    cube: RigidObject = sim.add_rigid_object(
+        cfg=RigidObjectCfg(
+            uid="cube",
+            shape=CubeCfg(size=[0.1, 0.1, 0.1]),
+            body_type="dynamic",
+            attrs=RigidBodyAttributesCfg(
+                mass=1.0,
+                dynamic_friction=0.5,
+                static_friction=0.5,
+                restitution=0.1,
+            ),
+            init_pos=[0.0, 0.0, 1.0],
+        )
+    )
+
+    usdpath = "/home/xiemh/model/004_sugar_box/004_sugar_box_xmh.usda"
+    sugar_box: RigidObject = sim.add_rigid_object(
+        cfg=RigidObjectCfg(
+            uid="sugar_box",
+            shape=MeshCfg(fpath=usdpath),
+            body_type="dynamic",
+            init_pos=[0.2, 0.2, 1.0],
+            use_usd_properties=True,
+        )
+    )
+
+    # Add objects to the scene
+    h1: Articulation = sim.add_articulation(
+        cfg=ArticulationCfg(
+            uid="h1",
+            # fpath="/home/xiemh/model/Collected_ur10/ur10.usd",
+            fpath="/home/xiemh/model/Collected_h1/h1.usda",
+            build_pk_chain=False,
+            init_pos=[-0.2, -0.2, 1.0],
+            use_usd_properties=False,
+        )
+    )
+
+    print("[INFO]: Scene setup complete!")
+    print("[INFO]: Press Ctrl+C to stop the simulation")
+
+    # Run the simulation
+    run_simulation(sim)
+
+
+def run_simulation(sim: SimulationManager):
+    """Run the simulation loop.
+
+    Args:
+        sim: The SimulationManager instance to run
+    """
+
+    # Initialize GPU physics if using CUDA
+    if sim.is_use_gpu_physics:
+        sim.init_gpu_physics()
+
+    step_count = 0
+
+    try:
+        last_time = time.time()
+        last_step = 0
+        while True:
+            # Update physics simulation
+            sim.update(step=1)
+            time.sleep(0.03)  # Sleep to limit update rate (optional)
+            step_count += 1
+
+            # Print FPS every second
+            if step_count % 100 == 0:
+                current_time = time.time()
+                elapsed = current_time - last_time
+                fps = (
+                    sim.num_envs * (step_count - last_step) / elapsed
+                    if elapsed > 0
+                    else 0
+                )
+                # print(f"[INFO]: Simulation step: {step_count}, FPS: {fps:.2f}")
+                last_time = current_time
+                last_step = step_count
+
+    except KeyboardInterrupt:
+        print("\n[INFO]: Stopping simulation...")
+    finally:
+        # Clean up resources
+        sim.destroy()
+        print("[INFO]: Simulation terminated successfully")
+
+
+if __name__ == "__main__":
+    main()