Posted by NoThisIsStupiderWhen importing your model, you'll see a table of the names of the textures on your model and a bunch of the number 0 beside the texture names. Replace the 0's with 1's and your good to go.
I have it set to 1. But some/few texutues have no collision.
edit:
If I go to a straight surface after a sloping surface, I fall into the ground. (No collision)
edit 2:
As walkable, must I use the front or the back surface?