[Feature] Mujoco import requires conaffinity and contype

[danx0r]

importing a mujoco (mjcf) model like so:

gs.morphs.MJCF(file='mujocomodel.xml')

Expected result: all elements of the Mujoco model imported

Actual result: geoms are ignored (do not load) unless I explicitly define the attributes conaffinity="0" contype="0"

[Kashu7100]

Please refer to #287 (comment) for the current supported objects in mujoco.

@danx0r Can you provide an example .xml (with object file if applicable) that you meet the problem?

[danx0r]

There is no need to upload an example, this behavior is exactly what is discussed in #287. It's a matter of deciding what you will support, but also what defaults to use. It is counter-intuitive to import a model and have it not visualize all the parts. At a minimum there should be some sort of warning message.

Possibly if I had RTFM closely I would have seen this caveat, but honestly I don't see why this would be the default behavior. It is in my experience standard practice to have mesh objects visualize even if they don't collide, so I would suggest that contype=conaffinity=0 be the default, and then ppl will seek out docs to explain how to add collision meshes or primitives.