0 to 1 uv?

Does anyone know what a 0 to 1 uv is? I found it referenced here:

http://www.chrisalbeluhn.com/Texture_Density_Tutorial.html

I have no idea what that means. Is it an Autodesk specific term, or does it apply to Blender textures as well?

UV space is a shared construct with all of the 3D programs, initially a bit confusing. The UV space is flat, with U being left to right and V being up and down. The lower left corner of this space is 0,0 going to 1 at the top and right edge. If you are working with ZBrush, or normal maps or baking of any assets, all of the “islands” in this UV space should not overlap, and fit into the upper right quadrant of the UV space. You will get errors and problems if these rules are not followed when doing the described operations. However, if you are just working on your own, without these operations, you can put your islands anywhere in the four(4) quadrants, but understand that the texture repeats, left and down, from the original UV space. Do some research, as dialogue has it’s limits.
Each has it uses, but generally you are safer to just use the upper right quadrant with no overlaps of the islands.
…+1
|------V-------|
| … |… |
|… |… |
-1----0,0-----+1 U
| … |… |
|… |… |
|------V-------|
…-1

So, I would be correct in assuming that the space that Blender uses for its UV unwrap would also be in quadrant 1?

Yes, all programs that I know of, will automatically UnWrap into the upper right quadrant. Blender doesn’t even show the other three(3), that I yet know how to show??? but other programs let you see them. Sometimes I find it useful to temporarily move islands into the other three(3) spaces when I am re-arranging them. Occasionally for some projects, I will let an island stretch across, but by default Blender and all other 3D programs will UnWrap their UVs into the upper right quadrant.

Makes sense. I have a lot to learn as far as texturing goes. Thanks for your help everyone.