Pieces With Mirrored UVs Have Normal Errors In July xNormal Workflow

TychoVII

This is a continuation of this thread.

I'm using the new xNormal workflow in the July UDK build to achieve normals without shading errors on a model with 1 smoothing group, but a problem arrises for all my pieces that have been mirorred/symmetried that share the same UV space.



When I flipped the green channel, the normals for that piece worked while the normals for the rest of the model received errors. So, for some reason the green is mirrored for that one piece and UDK doesn't know how to deal with it. At least that's as far as I can tell.

I've tried different FBX versions, mirroring, symmetry, both before and after baking, offsetting the mirrored piece by 1 in UV space, but nothing seems to change. I'm using the latest version of xNormal and Max 2011, and I know I've got all the correct FBX export and UDK import options selected according to Epic's instructions. Is anyone else having this problem with the new workflow?

Just to be clear, there are no lightmaps on this model, this is all in the material editor preview.

I'm uploading the model in question for anybody who's interested:
Low Poly
High Poly

cptSwing

Are you importing as Static or as Skeletal mesh? The latter can leave you in a world of pain, as I've found out recently ;-)

TychoVII

Just a static mesh. This model won't be intended for anything fancy, I just need it to look correct with a basic UDK setup.

danRod

wo no answer on this huh, I am seeing the same problem

JonathanLambert

I've had this problem too. The way I got around it was to not import the tangents from the fbx and to make sure the UVs are offset 1.0 on the U axis.

JamesWild

If you're not importing the tangents you're throwing away the synched pipeline AFAIK.

Try moving the mirrored geometry's UVs 1.0 along U as above, flipping around 1.5 on U, and then setting the textures' repeat type to mirror wrap. It should re-invert the tangents causing the problem. Though I don't know for sure as this problem doesn't appear to apply to all.

JonathanLambert

Yeah, I've pretty much given up on using the synced pipeline for meshes that use mirroring and just bake those out in max. I'll have to give your method a try.

JamesWild

I have no idea if it'll actually work or not, just an idea.

TychoVII

JamesWild wrote: »

Try moving the mirrored geometry's UVs 1.0 along U as above, flipping around 1.5 on U, and then setting the textures' repeat type to mirror wrap. It should re-invert the tangents causing the problem. Though I don't know for sure as this problem doesn't appear to apply to all.

I'm not quite sure what you mean by "flipping around 1.5 on U" or this setting of a repeat type. Where is this setting?

JamesWild

TychoVII

Ahh I see now. That's a pretty clever idea. I did this to my unwrap:



Unfortunately it still didn't seem to have an effect.
I brought it into Unreal and those mirrored pieces were definitely in the wrong UV space, so I know I imported it correctly. I then changed their Address X to mirror on the normal map and the pieces aligned correctly, but the shading artifacts were still there. So it would appear it doesn't work, which sucks because I had some hope for this technique.

JamesWild

Ah sorry about that man I was hoping that might be a functional workaround.

TychoVII

No worries man! It was an excellent idea. Guess we just can't rely on this synced pipeline yet