ZBrushCentral

inverted normal map problem

ZBrush Usage Questions
#1

Hey guys,

This issue has probably been encountered before, but I couldn’t seem to find any relevant threads…

Basically the problem is that on one 1 half of the model, the normal map is bumping in the opposite direction to the other half.

Image - http://1.bp.blogspot.com/_2UHZbVmIt2…asdsd+copy.jpg

Now my first reaction was to check the normal directions, and yes they are all conformed and facing the correct direction on BOTH halves of the model.

Image - http://1.bp.blogspot.com/_2UHZbVmIt2…-h/normals.jpg

Because it’s a low poly game model, I only UV mapped one half of the model, then duplicated and flipped it over, combined, then merged verts, the intention being to save as much texture space as possible. Everything’s asymetrical basically. However, I remember someone telling me that maya’s Uv’s actually have their own normals, and so this is probably why the bump is inverted on the mirrored half of the model.

Image - http://3.bp.blogspot.com/_2UHZbVmIt2…600-h/UVTE.jpg

I’ve tried all the usual suspects, deleting history/freeze transform/centre pivot, before I mirror the geometry. Tried duplicate with special, and mirror geometry, all to no avail.

There has to be a way around this as I’ve seen other people’s work with the same UV mapping layouts (2 sets of uv’s on top of eachother). Any help would be greatly appreciated guys, this thing’s been driving me nuts all day. Please let me know what you think.

Thanks.

#2

I think you just need to take 1 half of all symmetried UV’s and simply tile them over by exactly 1 unit to prevent from re-calculating the normals twice. So, if you can arrange the other half onto a new 1x1 UV layout and try re-doing the normal bake, it should work. I hope I explained it properly here, I know I’ve read of this solution elsewhere.