Strange normal map behavior in UDK (pics)

ktacreations

I have a character that uses mirrored UVs on their limbs. I managed to get rid of most of the seam problems (TCNormalMap you know how it is) but UDK is inexplicably reversing the normals on one of each limb. First pic is UDK, second is how it looks in Maya:




I had a similar issue in mental ray and fixed it by checking "maya derivatives" in the MR options. No such option exists in UDK and I'm at a loss. Any help? Thank you!

Oniram

http://udn.epicgames.com/Three/LightMapUnwrapping.html#Mirroring%20UVs

ktacreations

Thanks but that didn't have anything to do with the problem I described. The problem is not seams and I'm not using a lightmap. The problem is I can't get UDK to stop inverting the normals on stacked UVs.

Ace-Angel

Did you offset the UV's?

ktacreations

what do you mean? the UVs are stacked on top of eachother.

excellent avatar, by the way

m4dcow

Make sure you invert the green channel on your normal map if you are coming from maya.

igi

Did you flipped your mirrored UV pieces? And also you can move the mirrored UV's exactly 1 unit up or side onto the 0-1 UV space instead of stack them top of each other.

I think it would be easier to find the problem if you show your UV's to us.

ktacreations

Thanks guys. I've tried flipping the green channel and it didn't appear to do anything (baked normals in xnormal). I also tried mirroring the flipped UVs over into the 0/-1 space instead of stacking them but got the same issue. Here's my UVs:

It's only a few of the stacked UV shells that do it and, even stranger, it's the leg with the NON-flipped UVs that inverts. ARGH.


Many thanks, all!