Global position of a site

[yaswhar]

Intro

Hi everyone!

I'm a grad student at SUT, I use MuJoCo for my research on robotic manipulation.

My setup

MuJoCo Version: 3.3.1
API: Python

My question

I'm trying to get the global cartesian position of a site but the output is just [0. 0. 0.]. I don't know which part of my implementation is wrong, I've tried it with bodies and geoms and still got the same issue.

Minimal model and/or code that explain my question

print(data.site_xpos[mujoco.mj_name2id(model, mujoco.mjtObj.mjOBJ_SITE, "site_name")])

Confirmations

• I searched the latest documentation thoroughly before posting.
• I searched previous Issues and Discussions, I am certain this has not been raised before.

[kevinzakka]

1. You can just do data.site(site_name).xpos
2. Did you call mj_forward before reading the position? Presumably you are doing this right after initializing the model and data?

[yaswhar]

Thanks you Kevin!