Hard-Surface Normals - Curved object
I ran into a problem while UVing a test object to get the best understanding of how to tackle certain geometry involving a scenario where if needed to, I'd have to create hard-surface Normals. The issue isn't so much the creation of the Normal map, but rather the blending of the color values and such. I might have mixed the terminology, but I know that depending on your choice of smoothing, you'd want to average the blend with edge padding.
On SET 1, I took the polygons consisting of different normal facing and put an edge in-between them to give to different sets of UV islands, then attached them together, relaxed and split them. I did this because I wanted the padding to bleed on both sides.
On SET 2, I just simply detached the different facing normal face and relaxed, leaving them be. It doesn't look like it made much difference though. Maybe there wasn't enough padding in the baking. Again, I might be mixing this entire thing up with smoothed surfaces and I apologize if I am, but my study here was how to tackle these curved areas so that my UV's were efficient.
Thank you for your time!
On SET 1, I took the polygons consisting of different normal facing and put an edge in-between them to give to different sets of UV islands, then attached them together, relaxed and split them. I did this because I wanted the padding to bleed on both sides.
On SET 2, I just simply detached the different facing normal face and relaxed, leaving them be. It doesn't look like it made much difference though. Maybe there wasn't enough padding in the baking. Again, I might be mixing this entire thing up with smoothed surfaces and I apologize if I am, but my study here was how to tackle these curved areas so that my UV's were efficient.
Thank you for your time!
Replies
If you are talking about hard edge normals (aka smoothing splits) then you'll want to place them in the same location as your UV islands.
I'm not sure what you mean by this. If you're talking about tweaking your normal map in Photoshop after baking: I would say if you need to do this to a normal map along UV borders then you're not setting up your model to bake properly.
As for the UV layout, it just depends on how much distortion you can tolerate versus conserving UV space. I would probably unwrap that curved portion something like this:
The top version has beveled edges and one large UV island. The bottom version is similar to yours and the UVs have been split along 90 degree angles, as you should do in most cases, and the smoothing splits also match. I would prefer using the one with beveled edges because it means fewer UV islands to deal with. But of course, it all depends on your budget, target platform, etc.
Some links that expand upon what Bartalon said about splits:
http://tech-artists.org/wiki/Beveling
http://www.polycount.com/forum/showthread.php?t=107196&page=1
a bit more intimate with Straight UV's, Quack.