Is it possible to make a given actor semi-transparent?

As, per title.
I was searching for a method in gym’s API to set a specific actor transparency level (for both visuals and meshes), but I didn’t find it.
Setting it in the URDF material tag does not produce any effect.
Is there a way to do it?
If the answer was no, being able to turn off visual and mesh visualization for a single actor is also a viable alternative for me. Is there a way to perform the latter operation instead?