Implementing a weldjoint in MuJoCO (from OpenSim to MuJoCo)

[GraceNiyo]

I have an OpenSim model that I am converting to a MuJoCo model. In OpenSim a WeldJoint restricts any relative motion and maintains a fixed relationship between the bodies it connects. The bodies connected with a WeldJoint are permanently attached and cannot move relative to each other. What type of joint and constraints could I use in MuJoCo to create a "WeldJoint" equivalent. I looked at MuJoCo documentation on the available joint types but none of the joint types works.

[yuvaltassa]

https://mujoco.readthedocs.io/en/latest/XMLreference.html#equality-weld

[GraceNiyo]

thank you so much.