UDK normal map / shading issues

MrFrags

Hi polycount ! I'm working on a scene based on a concept of Viktor Jonsson;
I did a quick blockout of the scene and I started to create some HP elements.
Just for testing, I tried to export a little mesh to UDK... and I get some problems.
I tried to import into UDK my mesh with .ASE and .FBX formats, making sure to check "explicit normals" but in both cases the result is the same. I have shading issues, or maybe smoothing groups issues, anyway I have artifacts !
I already swap my Y channel in the normal map for UDK (I performed the baking in maya)

Has anyone had this problem? Is there any way to fix it?

Thank you !

gsokol

I don't really think explicit normals is going to be helpful in maya bakes.

Either way, if you bake in Maya, your going to have to flip your green channel since the tangent basis is different. Give that a shot.

MrFrags

gsokol wrote:

I don't really think explicit normals is going to be helpful in maya bakes.

I thought it would be helpful, because I felt that my mesh does not retain its smoothing groups. I've inverted the green channel in my normal map, but the problem persists!

m4dcow

Maya is not synced to UDK anyway, and with you having hard edges but still having those hard edges still connected in the UV map there are abrupt shading changes on your normal map.

Rule of thumb is wherever you have a hard edge you should have a split in the UV map.

MrFrags

Hum, my uv's islands are not connected, but the space between each island is maybe too low; generally when I get errors about uv's island, I get errors in maya.
Here a picture with bigger resolution:

m4dcow

Well like I said, because Maya and UDK aren't synced you will get those shading errors especially at hard edges etc..

I would say make sure you smooth those bevels and/or if you don't want too much gradient on your planar surfaces which can lead to smoothing errors also, you can fillet the vertex normals. (search for MIG Normal tools to do this)