[Bug Report] Visual Material not working for Articulation

[xindonglin99]

Describe the bug

I found that if I applied a visual material to an articulation, the InteractiveScene is not working properly and also the color is somehow bugged out.

Here is a screenshot of both, picture 1 shows only one character is moving, picture 2 everything works fine. See the following section for details.

Steps to reproduce

I'm running the tutorial file create_scene.py but replaced the CARTPOLE_CFG with HUMANOID_CFG. Here is the code for create_scene.py

# Copyright (c) 2022-2025, The Isaac Lab Project Developers.
# All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause

"""This script demonstrates how to use the interactive scene interface to setup a scene with multiple prims.

.. code-block:: bash

    # Usage
    ./isaaclab.sh -p scripts/tutorials/02_scene/create_scene.py --num_envs 32

"""

"""Launch Isaac Sim Simulator first."""


import argparse

from isaaclab.app import AppLauncher

# add argparse arguments
parser = argparse.ArgumentParser(description="Tutorial on using the interactive scene interface.")
parser.add_argument("--num_envs", type=int, default=16, help="Number of environments to spawn.")
# append AppLauncher cli args
AppLauncher.add_app_launcher_args(parser)
# parse the arguments
args_cli = parser.parse_args()

# launch omniverse app
app_launcher = AppLauncher(args_cli)
simulation_app = app_launcher.app

"""Rest everything follows."""

import torch

import isaaclab.sim as sim_utils
from isaaclab.assets import ArticulationCfg, AssetBaseCfg
from isaaclab.scene import InteractiveScene, InteractiveSceneCfg
from isaaclab.sim import SimulationContext
from isaaclab.utils import configclass

##
# Pre-defined configs
##
from isaaclab_assets import CARTPOLE_CFG, HUMANOID_CFG, ANT_CFG, HUMANOID_28_CFG, WALKER_CFG  # isort:skip


@configclass
class CartpoleSceneCfg(InteractiveSceneCfg):
    """Configuration for a cart-pole scene."""

    # ground plane
    ground = AssetBaseCfg(prim_path="/World/defaultGroundPlane", spawn=sim_utils.GroundPlaneCfg())

    # lights
    dome_light = AssetBaseCfg(
        prim_path="/World/Light", spawn=sim_utils.DomeLightCfg(intensity=3000.0, color=(0.75, 0.75, 0.75))
    )

    # articulation
    cartpole: ArticulationCfg = HUMANOID_CFG.replace(prim_path="{ENV_REGEX_NS}/Robot")


def run_simulator(sim: sim_utils.SimulationContext, scene: InteractiveScene):
    """Runs the simulation loop."""
    # Extract scene entities
    # note: we only do this here for readability.
    robot = scene["cartpole"]
    # Define simulation stepping
    sim_dt = sim.get_physics_dt()
    count = 0
    # Simulation loop
    while simulation_app.is_running():
        # Reset
        if count % 500 == 0:
            # reset counter
            count = 0
            # reset the scene entities
            # root state
            # we offset the root state by the origin since the states are written in simulation world frame
            # if this is not done, then the robots will be spawned at the (0, 0, 0) of the simulation world
            root_state = robot.data.default_root_state.clone()
            root_state[:, :3] += scene.env_origins
            robot.write_root_pose_to_sim(root_state[:, :7])
            robot.write_root_velocity_to_sim(root_state[:, 7:])
            # set joint positions with some noise
            joint_pos, joint_vel = robot.data.default_joint_pos.clone(), robot.data.default_joint_vel.clone()
            joint_pos += torch.rand_like(joint_pos) * 0.1
            robot.write_joint_state_to_sim(joint_pos, joint_vel)
            # clear internal buffers
            scene.reset()
            print("[INFO]: Resetting robot state...")
        # Apply random action
        # -- generate random joint efforts
        efforts = torch.randn_like(robot.data.joint_pos) * 5.0
        # -- apply action to the robot
        robot.set_joint_effort_target(efforts)
        # -- write data to sim
        scene.write_data_to_sim()
        # Perform step
        sim.step()
        # Increment counter
        count += 1
        # Update buffers
        scene.update(sim_dt)


def main():
    """Main function."""
    # Load kit helper
    sim_cfg = sim_utils.SimulationCfg(device=args_cli.device)
    sim = SimulationContext(sim_cfg)
    # Set main camera
    sim.set_camera_view([2.5, 0.0, 4.0], [0.0, 0.0, 2.0])
    # Design scene
    scene_cfg = CartpoleSceneCfg(num_envs=args_cli.num_envs, env_spacing=2.0)
    scene = InteractiveScene(scene_cfg)
    # Play the simulator
    sim.reset()
    # Now we are ready!
    print("[INFO]: Setup complete...")
    # Run the simulator
    run_simulator(sim, scene)


if __name__ == "__main__":
    # run the main function
    main()
    # close sim app
    simulation_app.close()

And here's the HUMANOID_CFG

# Copyright (c) 2022-2025, The Isaac Lab Project Developers.
# All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause

"""Configuration for the Mujoco Humanoid robot."""

from __future__ import annotations

import isaaclab.sim as sim_utils
from isaaclab.actuators import ImplicitActuatorCfg
from isaaclab.assets import ArticulationCfg
from isaaclab.utils.assets import ISAAC_NUCLEUS_DIR

##
# Configuration
##

HUMANOID_CFG = ArticulationCfg(
    prim_path="{ENV_REGEX_NS}/Robot",
    spawn=sim_utils.UsdFileCfg(
        usd_path=f"{ISAAC_NUCLEUS_DIR}/Robots/Humanoid/humanoid_instanceable.usd",
        rigid_props=sim_utils.RigidBodyPropertiesCfg(
            disable_gravity=None,
            max_depenetration_velocity=10.0,
            enable_gyroscopic_forces=True,
        ),
        articulation_props=sim_utils.ArticulationRootPropertiesCfg(
            enabled_self_collisions=True,
            solver_position_iteration_count=4,
            solver_velocity_iteration_count=0,
            sleep_threshold=0.005,
            stabilization_threshold=0.001,
        ),
        copy_from_source=False,
        activate_contact_sensors=True,
        # visual_material=sim_utils.PreviewSurfaceCfg(
        #     diffuse_color=(0.0, 1.0, 0.0),
        #     emissive_color=(1.0, 0.0, 0.0),
        #     metallic=0.2,
        # ),
    ),
    init_state=ArticulationCfg.InitialStateCfg(
        pos=(0.0, 0.0, 1.34),
        joint_pos={".*": 0.0},
    ),
    actuators={
        "body": ImplicitActuatorCfg(
            joint_names_expr=[".*"],
            stiffness=0.0,
            damping=0.0,
        ),
    },
)
"""Configuration for the Mujoco Humanoid robot."""

If I put the visual material in the HUMANOID_CFG, the interactive scene will only have 1 moving character. The others are frozen. If I comment out the visual material, every character is able to move. I wonder if there's a bug for the articulation's visual material since I can do this fine with RigidBody class.

Checklist

• I have checked that there is no similar issue in the repo (required)
• I have checked that the issue is not in running Isaac Sim itself and is related to the repo

Acceptance Criteria

Add the criteria for which this task is considered done. If not known at issue creation time, you can add this once the issue is assigned.

• A corresponding color is shown according to the user's cfg.
• All the characters can move after creating the InteractiveScene.