UV coordinates on a deformed plane I added a plane to a scene, subdivided it, and deformed it with proportional editing:



I'd like to UV unwrap this plane, making the mapping what the would have been without the edit mode deformations. In other words, I'd like my UV map to look like a square grid.

Is it possible to UV map this deformed plane to a square grid? Or do I need to start from scratch, and make sure I unwrap it before I do the edits?
It is simple to unwrap a deformed plane like in your image, back to a square UV map.

In face select mode, select all the faces with A and make one of the faces active.
Then press U > Follow Active Quads and then choose Even and press OK.

This will give you a even square UV layout.