Frame editing change not reflected in model

[martantoine]

Intro

Hi!

I am a graduate at EPFL, I use MuJoCo for my master thesis.

My setup

When trying to modify body position and orientation in MuJoCo 3.3.4, I've found that directly editing mjsBody or mjsFrame doesn't visually update the model, even though model->body_pos shows the correct values.

I have to delete and recreate bodies/geoms for changes to appear.

However, editing geom sizes works fine without recreating them.
This suggests the issue is how MuJoCo's mjSpec handles pose updates during compilation/recompilation, rather than a visualization problem (I'm creating new scenes and calling mjv_updateScene).

My question

Deleting to then re-add element is of course not an ideal implementation and I would like to instead use the FULL POWER of model editing, that is being able to correctly set my new frame values in MjSpec

What are you thoughts on that ?

Thanks!

Some code

  mjsBody* body = mjs_findBody(spec, "mybody");
  // Some random values..
  body->pos[0] = 1.0;
  body->pos[1] = 2.5
  body->pos[2] = 543.6;
  body->alt.type = mjtOrientation::mjORIENTATION_EULER;
  body->alt.euler[2] = 52.0;
  

Confirmations

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