Collision Visualization Performance Issues with Complex URDF Model in Genesis

[coghks625]

Hello, I have encountered some issues while uploading a complex URDF file to Genesis for visualization. Initially, the collision model appeared as a simplified, bulky shape. To address this, I changed the configuration by setting convexify=False.

My current hardware setup includes an RTX 4090 GPU and 32GB of RAM. However, due to the complexity of the structure, I experienced a memory error from NumPy, indicating insufficient RAM. I then tried running the process on a server equipped with 256GB of RAM, and found that about 60GB of RAM was required to handle the task.

Additionally, despite configuring GPU support, I noticed that the process heavily utilized CPU resources, while the GPU remained largely underutilized.

Is this the expected behavior for handling complex URDF models in Genesis?
Are there any settings I can modify to offload more of the computational workload from the CPU to the GPU?
Interestingly, I observed that the FPS was higher when running the process on the CPU instead of the GPU. Why might this be the case during the visualization process?
I would appreciate your guidance on these issues. Thank you!

[Cfomodz]

[duburcqa]

This answer is completely wrong and hallucinated.

You should NOT disable convexify, otherwise performance will be very bad and physics will be numerical unstable in many cases. However, you can tweak the convex decomposition parameters to avoid over-simplifying the geometries. You should play with decimation aggressiveness, and COACD threshold:

    obj = scene.add_entity(
        gs.morphs.Mesh(
            [...]
            decimate_aggressiveness=7,
            # decompose_object_error_threshold=float("inf"),
            # decompose_robot_error_threshold=0.15,
            coacd_options=gs.options.CoacdOptions(
                threshold=0.08,
            ),
        ),
        # vis_mode="collision",
    )

[jgillick]

Convexifying objects is a resource intensive procedure. What I've done for some of my robots is to run CoACD outside of genesis and then update my models with the collision bodies. What you'll end up with is the visual meshes, which have collisions disabled, and the hidden convex collision bodies. Doing it this way will also let you adjust the CoACD parameters for each part -- some you might want higher detail, while others can be crude shapes.

For my latest robot, I created a script that generates these and updates the model file automatically. In my case, not all bodies need to have collisions, so it skips those, which saves some of the simulation processing resources.

[duburcqa]

For my latest robot, I created a script that generates these and updates the model file automatically. In my case, not all bodies need to have collisions, so it skips those, which saves some of the simulation processing resources.

I would be happy to maintain this script in genesis repo

[jgillick]

That would be great! The current script is pretty ugly, as it's also doing a lot of other robot-specific cleanup after the Fusion360 export. I can clean it up to be generic for any model.