Normap map extraction problem with ZBrush

splinter · Jul 2012

Hi,

I'm new in 3D and I've got a problem trying to extract normal map with ZBrush. It looks pretty nice, except for the faces near the corners. I made a default extraction, the first one is with SNormals and the second one without it. Note that with SNormals it doesn't seem to cover the entire faces in the up and down corners (I've put those lines in the first image just to compare with the unwrapped map, they don't actually exist in the normal map image):

And when I render the map with SNormals it doesn't seem to work fine in the corners:

Anyone know how to solve it?

Thanks in advance!

Bek · Jul 2012

What exactly is the last image, the model? How is it rendered / how is it getting the normal map? Tried baking the normal map in xNormal?

cryrid · Jul 2012

I'd check the UV's in another program to make sure the borders are all welded, and not broken into flipped islands.

If there's no particular reason to bake in zbrush though, you'll probably be better off baking in an external program due to the extra options and control.

splinter · Jul 2012

Thanks for the replies. Here's the process so you can view it better:

http://img220.imageshack.us/slideshow/webplayer.php?id=78619875.jpg

Edit: I tried exporting with xNormal and I think I found something that can help to discover the solution. I unchecked "Discard back-face hits" and the colorized areas in the image shows the faces that are not correct with the normal mapping:

Anyone know how to fix it?

Internet Friend · Jul 2012

When you subdivide a mesh in ZBrush, it modifies the base mesh that it later uses to bake a map from. In this case you've got a a mesh with two open ends with no control edges around them; subdividing will cause those open ends to contract. Do this: Import your base mesh, store a Morph Target, subdivide your mesh and maybe do a little sculpting, then drop down to the lowest subd level and switch MT back and forth. You should see what I mean.

One way to get around this is to switch back to the original MT before exporting the map, but you might get screwy results because of how much it is shrinking. I think the thing to do here is add some edges around the open ends & bake to your low poly in xNormal.

splinter · Jul 2012

Thanks for the tips. I'll try to do that!

Normap map extraction problem with ZBrush

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