Smoothing Groups, Cage, UVW Split

Jessica Dinh

Hello!

I am making a low poly object and baking a normal map for it from a high poly version. I am planning to use cages for normal map projection since most of my pieces have 90 degree angles on them. I have a question about how to unwrap my low poly object. I understand that wherever there are 90 degree angles I must give each section its own smoothing group, and that there must be a uvw break where all 90 degree angles are - but does that necessarily mean each smoothing group has to have its own uvw island? I hope I'm making sense.

Thanks!
Jessica

KyleJensen

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Edit: Question misunderstood.

Dis

Shad0wForce wrote: »

Eliminate 90 degree angles in the low poly by simply adjusting them or chamfering the edges/verts and have every piece of the low poly is at 1 smoothing group. You can start unwrapping the model from there.

Circumventing a problem (that isn't really a problem) by throwing more tris at it as a rule of thumb is just dumb. There are a lot of sides to when to chamfer or use hard edges/smoothing groups and so on so check http://wiki.polycount.com/NormalMap#SmoothingGroupsAndHardEdges for info on it.

Now, what you said (Jessica) is all correct. If you don't split the hard edges in the UVs, those edges will become black when the normal map is baked. I could just misunderstand you but I think you'll find that once you start splitting where the hard edges are, the UV islands come pretty naturally. One smoothing group doesn't have to be one UV island though, you can split it into more pieces if you think that's better.

Jessica Dinh

Why thank you! Your answer was very straightforward. Yes, I understand now, I just had to go ahead and tackle it - it wasn't too hard to figure out, I just had to be careful. Thanks!