How do I make Pathfinding only go on certain parts?

What I am trying to do is make it so a rig will move along a path without touching the floor part.

I want it to not touch the red part but it can touch and walk on every other part and walk too the black dot:

(I used colors to show that it is different parts, I don’t want it to not walk on the color red, I just want it to not walk on that certain part.)

You can use the Pathfinding Modifiers to make walking over the red part undesirable. Check the following article and scroll down to the Pathfinding Modifiers section: