fix(URDF): meshes loading failing

[mayank0621]

Hi,
When I'm trying to launch ros2 launch inmoov_ros_sim main.launch.py I'm getting error as shown in the image. I think Texture.261.stl, Texture.262.stl, Texture.265.stl, Texture.266.stl files are corrupted. I'm using Ubuntu22.04 with ROS2 Humble.

I can only see upper body of humanoid as shown in above image.

[charlesmadjeri]

Hi @mayank0621, thanks for your feddback.
This project is in pre-alpha so it's not surprising that you got a bug.
We're currently focusing on building a fully inmoov i2 working URDF with ros2_control tags.

If you're interesting in submitting a fix or investigating, feel free. We will need some time (to work on this issue on our side.
You can find here the inmoov_urdf repository

Still, this project need a dependency check:

• Check mentioned URDF meshes files (fix maybe required also on inmoov_urdf repository
• For the legs its a regular behavior, as the exported URDF did'nt contain legs but only a stand (we can create several different URDF, adding one with legs)

[mayank0621]

Thanks @charlesmadjeri for your response. I've tried meshes from inmoov_urdf repository repositry but still getting same error. I would like to contribute to this project.

[DonCe42]

@mayank0621 Do you resolved the problem with meshes loading falling?

[Nojahhh]

Those meshes fails to load in the ROS2 sim due to missing inertial blocks.

A wild guess based on the vibe-coded help I got to solve this was that they were probably built as empty placeholders from blender or other modeling software, but that's a wild guess, don't take my word for it as I'm very new to this field but when previewing the stl models I only see an empty plane so I guess it might be true.

My solution was to add inertial blocks with very small mass for visual-only links to those stl mesh file links from the urdf file and then I got it running. I'm using ROS2 Jazzy and Gazebo Harmonic for simulation on Ubuntu 24.04.

Here's the script I ran that injects the inertial properties:

#!/usr/bin/env python3
"""
Script to add default inertial blocks to URDF links that don't have them.
This is required for Gazebo Harmonic simulation.
"""

import re
import sys
from pathlib import Path

def add_inertial_to_links(urdf_path: str):
    """Add default inertial blocks to links without them."""
    
    with open(urdf_path, 'r') as f:
        content = f.read()
    
    # Default inertial block (small mass for visual-only links)
    default_inertial = '''    <inertial>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <mass value="0.1"/>
      <inertia ixx="0.001" ixy="0.0" ixz="0.0" iyy="0.001" iyz="0.0" izz="0.001"/>
    </inertial>'''
    
    # Find links that already have inertial
    has_inertial = set()
    inertial_pattern = re.compile(r'<link name="([^"]+)"[^>]*>.*?<inertial>.*?</inertial>.*?</link>', re.DOTALL)
    for match in inertial_pattern.finditer(content):
        has_inertial.add(match.group(1))
    
    modified_count = 0
    
    # Process self-closing links: <link name="xxx"/>
    def replace_self_closing(match):
        nonlocal modified_count
        name = match.group(1)
        if name in has_inertial or name == 'world':
            return match.group(0)
        modified_count += 1
        return f'''<link name="{name}">
{default_inertial}
  </link>'''
    
    content = re.sub(r'<link name="([^"]+)"\s*/>', replace_self_closing, content)
    
    # Process normal link blocks without inertial
    link_block_pattern = re.compile(r'(<link name="([^"]+)">)((?:(?!</link>).)*)(</link>)', re.DOTALL)
    
    def process_link_block(match):
        nonlocal modified_count
        opening_tag = match.group(1)
        name = match.group(2)
        content_inside = match.group(3)
        closing_tag = match.group(4)
        
        if name == 'world' or '<inertial>' in content_inside:
            return match.group(0)
        
        modified_count += 1
        return opening_tag + '\n' + default_inertial + content_inside + closing_tag
    
    content = link_block_pattern.sub(process_link_block, content)
    
    # Write modified content
    with open(urdf_path, 'w') as f:
        f.write(content)
    
    print(f"Added inertial blocks to {modified_count} links")
    return modified_count

if __name__ == '__main__':
    if len(sys.argv) < 2:
        # Search for inmoov_ros_sim URDF automatically
        candidates = list(Path.cwd().rglob('inmoov_ros_sim/urdf/sentience_gz.urdf'))
        if not candidates:
            print("Error: Could not find 'sentience_gz.urdf' in any 'inmoov_ros_sim/urdf/' folder")
            sys.exit(1)
        urdf_path = candidates[0]
    else:
        urdf_path = Path(sys.argv[1])
    
    if not urdf_path.exists():
        print(f"Error: URDF not found at {urdf_path}")
        sys.exit(1)
    
    print(f"Processing: {urdf_path}")
    add_inertial_to_links(str(urdf_path))
    print("Done!")