Need help understanding urdf and tf
I've worked through the tutorials on urdf and am working through tf. I have created a urdf for my physical robot. I am striving to get my robot set up to use the Nav stack and somehow had in my mind that the urdf is required and a step towards setting up the transforms for the robot, but if I read that somewhere I cannot now find it and am having a hard time getting my head wrapped around this. I understand why I need transforms, I'm starting to understand how to write the code for the transforms, I am quite confident in my abilities writing a urdf, but I don't see where, if anywhere, the two come together. Do I even need a urdf for a physical robot? I feel I am missing a big BIG part of the picture here and could use a good explanation or at least a nudge in the right direction.
