Is there a bone constraint that makes a bone perpendicular or parallel to a mesh?

And if not can someone invent it?

Which part of a mesh? Post some images please showing the problem and we can better help you.

Cheers, Clock.

Any part it’s closest too at all times, just a general question. I mean all I want is for a bone to look at the normal lines of a mesh, and then change the rotation of another bone to locally match those lines or be 90 degrees from them. The shrinkwrap modifier oddly enough does it almost where it makes a bone stick to the surface of a mesh, but it doesn’t change its rotation.