Second UV channel for lightmaps jumbled after import into UDK

RexM

Alright, here is the issue I am having. On the left are the uvs as they are in Maya, and on the right is what they end up as when importing into UDK. Has anyone run into this issue before?

r4ptur3

are you importing via FBX? Make sure you trash your history and freeze transforms before you export. FBX has a nasty habit of remembering that stuff :P

Also as a side note -- you might want to sew that stuff up. Unsewn UVs are going to give you nasty seams and add to your vert count.

RexM

Hi r4ptur3,

Yeah, using FBX. I definitely deleted history and froze transforms. Even tried combining the mesh to a cube, deleting the cube, and importing in to UDK again, of course deleting history and freezing transforms as well.

It's for a vegetation object, so that's why nothing is sewn. Very strange issue though, could the UV's be screwing up upon import into UDK? Weird stuff, hope I can figure it out somehow.

r4ptur3

Ah, gotcha. Yeah UDK can scramble UVs if you are importing multiple meshes and let UDK combine them. Is each leaf a different mesh? If so, try combining them first.

RexM

I made sure to combine using the standard combine option in maya before I exported. I do keep them separate when working on them, but then combine them for export.

r4ptur3

So strange ... every 4th vert is getting scrambled. Aside from checking the mesh myself, I am all out of ideas ; ;

ng.aniki

Hm, could you upload the .ma file with only the lowpoly and the fbx ? I can take a quick look to see if I have the same problem.

RexM

Just figured I would update this thread saying how I fixed it: I had to use the uv set editor to create a new uv set, the problem seemed to be with the create new uv set toolbox.

r4ptur3

so the end result was a static mesh with 2 UV sets, and that fixed it? oh UDK, you so silly. glad it got fixed! I would have never thought to do that -- I routinely bring meshes in with only 1 set.

RexM

Ah, so you create the second uv set all in UDK?

Yeah, it was sort of on a whim; I just search about how to create lightmap uvs in Maya to bring into UDK. Since the tutorial specified to use the uv set editor to create the second uv set instead of the 'create new uv set' toolbox, I gave that a try and that worked.