How does a weld equality dynamic activation affect contact information?

[NadeenElh]

Intro

Hi!

I'm a graduate student at Osaka University. I use MuJoCo for my research on RL Robotics.

My setup

I'm currently using mujoco version 3.3.2, python

My question

If I dynamically activate a dormant weld equality during simulation, where do the contact forces previously stored in data.cfrc_ext go? Say, part A is in contact with part B and initially, data.cfrc_ext contained [Fx, Fy, Fz]. When part A becomes welded to robot arm/gripper, it is still experiencing contact with part B but the cfrc_ext variable is now [0, 0, 0].

Is there a different variable that contains the A/B contact forces now? Or do I have to detour by figuring out the changes to the weld forces at the weld site and then transform them to the COM of part A?

Thanks in advance.

Minimal model and/or code that explain my question

No response

Confirmations

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• I searched previous Issues and Discussions, I am certain this has not been raised before.