Noisy net contact force on uneven mesh terrain


I created a simple cube object on an uneven mesh terrain (see picture below), and measure its net contact force and sensor force in CPU and GPU.

The force sensor is attached to the cube.

The GPU settings are:
physx.use_gpu = True
use_gpu_pipeline = True

Both of the above parameters are set to False for the CPU settings.

I am using Isaac Gym Preview 4.

I found that the net contact force values are noisy in both CPU and GPU (see pictures below). Is this a bug?

xy-values on GPU:

z-values on GPU:

z-values on CPU:

I am aware of the net contact force issue with the triangle meshes described in the Isaac Gym’s documentation: docs/programming/terrain.html
Are they related?

I also found that the sensor forces are slightly off. Is this a bug too?

What is the solution?