Symmetry problem with ZBrush normal map

splinter

I made these details with symmetry on:



But when I export the map one side is stronger than the other. I sculpted on the left side and due to symmetry, the right side was sculpted too. But the left side is deeper than the right:



I tried exporting from ZBrush and xNormal, no sucess in both. Anyone know what can it be?

Thanks in advance.

Kurt Russell Fan Club

Don't worry -- it's not deeper, it's just different colours because the normal map is flipped left to right and the ear's unwrapped on a slightly different angle.

The easiest way to see how steep an angle is in a normal map (steep meaning how divergent the normal is from directly up) is to look at just the blue channel. Your blue channel shows the left and right ear are practically identical.

splinter

Kurt Russell Fan Club wrote: »

Don't worry -- it's not deeper, it's just different colours because the normal map is flipped left to right and the ear's unwrapped on a slightly different angle.

The easiest way to see how steep an angle is in a normal map (steep meaning how divergent the normal is from directly up) is to look at just the blue channel. Your blue channel shows the left and right ear are practically identical.

I think I understood the theory, but I don't know why in practice the map is still showing the problem:

bugo

I'm not sure if you are doing this for a game realtime or prerendered. Be careful trying to bake normal maps in Zbrush, they are not accurate and they will bend your normals quite a lot after exporting if it's for game purposes.

As for the mirroring, did you try using smart simmetry on the ears?

splinter

bugo wrote: »

I'm not sure if you are doing this for a game realtime or prerendered. Be careful trying to bake normal maps in Zbrush, they are not accurate and they will bend your normals quite a lot after exporting if it's for game purposes.

As for the mirroring, did you try using smart simmetry on the ears?

It's prerendered. I tried xNormal too, but it gave me the same problem...

I used smart symmetry and I got the message "Symmetry result: full symmetry found". I'm sure I'm using a symmetrical model and it is showing symmetry in the sculpting. The problem is just when I generate the maps... I use GoZ to switch between 3DS and ZBrush.

Edit: I've found the solution. Since I'm using Mental Ray, I need to add an extra map called Normal Bump between Arch & Design and the bitmap file. Also, disable LUT.

Thanks anyway!