Skip to main content

Frequently Asked Questions

Simulation​

QACC Error:​

WARNING: Nan, Inf or huge value in QACC at DOF 1. The simulation is unstable. Time = 0.0600.

This is an instability error for your physical simulation in MuJoCo and may originate from many causes.

  1. Large joint force: Consider adding some damping or armature to your joints to mitigate abrupt force applications.
  2. Large time step: Try to reduce your time step size, e.g., from 0.005 to 0.002. For debugging purposes, you can set the timestep to an extremely small value (e.g., 1e-5) to test the stability of the simulation.
  3. Severe self-collision: The links of your model, whether it's a robot or an articulated object, might be generating very large collision forces. Review the collision mesh you are using to ensure it is accurate and not causing excessive force calculations.
  4. More stable integrator: If your system is particularly complex, consider changing your integrator within the <option> tag from Euler to RK4 for potentially improved stability.

Installation​

pip install stuck​

Building wheel for mujoco (setup.py) ... /

(stuck here)

If your pip install process is stuck, it could be due to several reasons:

  • Binary vs Source: You might be compiling from source because there is no pre-built binary wheel available for your system. This could happen if you're using an older system that does not support the manylinux2014 platform tag. In such cases, a binary distribution may not be suitable for your system.
  • Environment Variables: Ensure that you have set the environment variables MUJOCO_PATH and MUJOCO_PLUGIN_PATH correctly. These variables help the installer locate the necessary MuJoCo files on your system.

If you continue to experience issues, consider looking for any error messages that occur before the process gets stuck or checking the system's process manager for any indications of what the installation process is doing at the time it becomes unresponsive.