Cannot import urdf file into isaac sim using UI (URDF importer)

[ahn.paf]

I am trying to import urdf from armar · PyPI into isaac sim but there is nothing shown in my UI view and there is lots of error! What is the problem?
2023-10-02 13:41:54 [2,484,106ms] [Warning] [omni.isaac.urdf] Path: package://armar/description/meshes/armar6/collision/middle_neck.stl not found
2023-10-02 13:41:54 [2,484,106ms] [Warning] [omni.isaac.urdf] Failed to resolve mesh ‘package://armar/description/meshes/armar6/collision/middle_neck.stl’
2023-10-02 13:41:54 [2,484,106ms] [Warning] [omni.isaac.urdf] Prim /main/middle_neck/collisions not created
2023-10-02 13:41:54 [2,484,107ms] [Warning] [omni.isaac.urdf] ROS_PACKAGE_PATH not defined, will skip checking ROS packages
2023-10-02 13:41:54 [2,484,107ms] [Warning] [omni.isaac.urdf] Path: package://armar/description/meshes/armar6/visual/upper_neck.obj not found
2023-10-02 13:41:54 [2,484,107ms] [Warning] [omni.isaac.urdf] Failed to resolve mesh ‘package://armar/description/meshes/armar6/visual/upper_neck.obj’
2023-10-02 13:41:54 [2,484,107ms] [Warning] [omni.isaac.urdf] Prim /main/upper_neck/visuals not created
2023-10-02 13:41:54 [2,484,107ms] [Warning] [omni.isaac.urdf] ROS_PACKAGE_PATH not defined, will skip checking ROS packages
2023-10-02 13:41:54 [2,484,107ms] [Warning] [omni.isaac.urdf] Path: package://armar/description/meshes/armar6/collision/upper_neck.stl not found
2023-10-02 13:41:54 [2,484,107ms] [Warning] [omni.isaac.urdf] Failed to resolve mesh ‘package://armar/description/meshes/armar6/collision/upper_neck.stl’
2023-10-02 13:41:54 [2,484,107ms] [Warning] [omni.isaac.urdf] Prim /main/upper_neck/collisions not created

[toni.sm]

Hi @ahn.paf

Which of the .urdf files are you importing?
I can import armar4.urdf and armar6.urdf without any problem

[ahn.paf]

amar4.urdf! Am I doing everything correctly?I can see the prims but there is nothing in my viewport! when I play the scene I get this error:

[toni.sm]

Hi @ahn.paf

Respect to the [omni.isaac.urdf] Failed to resolve mesh 'package://armar/..., from your image, the urdf path has white spaces. Make sure that the path to your file has no white spaces.

Regarding the shape creation error, the indicated prims have sphere collisions with radius 0 in the urdf file.

<collision>
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <geometry>
        <sphere radius="0.00"/>
    </geometry>
</collision>

Set a positive non-zero value for the sphere radius to avoid this error.

[ahn.paf]

Thank you for your help;
Is the zero sphere parameter the problem with the original URDF? did you change them as well? I changed all the sphere radius to 1 and I get a sphere :D
What is actually happening? if I import another URDF with the correct sphere value it should work as expected?

[toni.sm]

Hi @ahn.paf

Please, choose a smaller value according to the robot scale (e.g.: 0.01).
The values should be in meters (if your Isaac Sim configuration is not changed).

[ahn.paf]

I think the problem is with the URDF file when I lower the sphere parameter to 0.01 it shows just to sphere!
Did you also change the URDF files? does it work for you?

[toni.sm]

Hi @ahn.paf

Also, follow this:

@toni.sm

Respect to the [omni.isaac.urdf] Failed to resolve mesh 'package://armar/..., from your image, the urdf path has white spaces. Make sure that the path to your file has no white spaces.

[ahn.paf]

I resolved that issue but the problem with the two spheres persists! You can see my path which has no white space
Is it from my URDF file?

[toni.sm]

Hi @ahn.paf

I think/guess you are only copying the urdf file and not the whole folder keeping its structures.
Here are the clean step to import the robot.

1. Cone or download the armar-urdf repository to a folder (in a path without white spaces: e.g. /home/amirhossein/Desktop)

2. Edit the armar4.urdf file (/home/amirhossein/Desktop/armar-urdf/armar/description/urdf/armar4.urdf) an set a (small) positive non-zero value for the sphere collision radius

3. Import the armar4.urdf from its location (/home/amirhossein/Desktop/armar-urdf/armar/description/urdf/armar4.urdf)

   Some notes about import (read more about it here: URDF Importer):

   • Uncheck Fix Base Link (since the robot is supposed to move in the world)
   • Uncheck Create Physics Scene and check Clear Stage for generating a clean .usd file for the robot.