[MJX] how to get body.id given body.name

[Kallinteris-Andreas]

Hi,

I'm a maintainer of Gymnasium & the project manager of Gymnasium-Robotics, and I'm trying to use MuJoCo-MJX for "prototyping MJX-based RL environments in Gymnasium, Gymnasium-Robotics, Metaworld, MO-Gymnasium".

I want the ID of a body part while knowing its name

with mujoco you can get the ID of a body part with:

data.body("torso").id

how can I do the same thing with MJX

Thanks!

[btaba]

Hi @Kallinteris-Andreas , for now you can use MuJoCo to get the id, and then use the id with MJX. Check out the colab where the BarkourEnv has examples of this

[varadVaidya]

hi @Kallinteris-Andreas , I am also in the process of converting my current custom MuJoCo Gymnasium environment to use MJX.
If possible can you share or point to a Minimal working example for such workflow. I am currently trying to take inspiration from MjxEnv in brax (as in the colab tutorial), but would love to see some other examples as well

[Kallinteris-Andreas]

@varadVaidya Keep it is WIP, but you could check out Farama-Foundation/Gymnasium#834