Where is Custom Geometry flag in Collider

Omniverse Isaac Sim
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1

Hi, I am trying to set up a custom geometry for train wheel colliders and found some threads talking about Custom Geometry. However, there’s no such option in the collider tab with the type Cylinder. Is there any step I missed?

The ISAAC Sim version is 2023.1.0 and my environment is Ubuntu 22.04. Here’s the screenshot.

Screenshot from 2023-11-14 02-09-24
Screenshot from 2023-11-14 02-09-241920×1090 121 KB

Thank you.

2

my understanding is when you do Add -> Physics -> Collider Preset on a shape (in this case, you do have a cylinder shape), it should create the custom geometry collider by default.

looks like you used Add -> Physics -> Rigid Body with Collider Preset, which should still be fine. are you experiencing unexpected simulation behaviors?

something tells me they may have removed that flag from earlier versions. but that’s something a mod/dev would be able to confirm.

3

Yes, the setting per prim was removed and replaced by USD stage setting. If you open Window->Simulation->Settings you can find it there:

image
image1304×548 109 KB

The rationale is, if you want to have it per prim, you can control it by either creating a capsule shape or capsule mesh. But you should still be able to control the behavior per stage.

Regards,
Ales

4

@AlesBorovicka that’s good to know it’s now under USD stage settings 👍

5

I see, thank you for the explanation.
I have another question, what will be the best way to simulate a flange wheel collider? It seems that the only two custom geometry settings are cones and cylinders only but not of them are close to the shape of a flange wheel.

Thank you in advance.

6

Currently you have two options:

  1. try convex decomposition and see if the results are acceptable
  2. use SDF collider which should give you correct collisions, however the memory consumption will increase, so it depends how massive your scene is if things will still fit into the GPU memory.

Regards,
Ales