In the isaac gym preview4 python example: spherical joint, the original urdf file defines 3 prismatic joint and then a spherical joint, but if you put the spherical joint ahead of 3 prismatic joint, the spherical joint will appear twice in the acquired dofs.
When using original urdf, the result is right:
But if you put some joints after spherical joint, the result is messed up
spherical_joint.urdf (1.5 KB)