Normal map seams after building lights

Sean VanGorder

So as the thread title says, every time I build my lights inside of UDK, I get seams on every hard edge of my normal map. I've tried every fix I could think of, but I'm hoping I'm just missing something simple. What confuses me is that it appears to be a perfect normal map, in every app, until I build lighting in UDK. Anyone know a fix for this?

Left is before building, right is after.


And I've ruled out it being a lightmap issue, as you can see below.

sprunghunt

can we see what the normalmap looks like?

Sean VanGorder

Sure.

This is after I went back and added even more padding between islands. Each island is a separate smoothing group.

Justin Meisse

what do your lighting UVs look like?

Sean VanGorder

Justin - It's pretty much the same as channel 1. Even if I weld them together for the lightmap uvs, I get the same issue.

ZacD

Did you check import tangents on import? What did you bake the normals in?

Sean VanGorder

I tried it with and without import tangents, and it looked worse with import tangents turned on. Normals are baked in Max, scanline renderer.

I'm currently trying to get max to export qualified normals correctly to see if that helps.

sprunghunt

I would just not split the UVs like that and bevel the edges of your box instead of using smoothing groups.

It's almost impossible to get decent smoothing across something that's been split like that.

Sean VanGorder

Yeah, I guess I could do that. Is that just a UDK thing that is causing it? Because like I said, the normal map looks fine in any other app.

sprunghunt

Sean VanGorder wrote: »

Yeah, I guess I could do that. Is that just a UDK thing that is causing it? Because like I said, the normal map looks fine in any other app.

I've never seen an actual game engine that treats seams differently. I'm guessing it runs faster like that and it's really not a big deal once you get used to it.

Oniram

you may also want to point out the lightmap issue when the seams are fixed. :P

r4ptur3

did you remember to flip your green channel?

Torch

Do you need to flip the green channel in the normal map? I've brought normal mapped meshes into UDK before without flipping any channels and they've looked fine.

Oniram

yeah its not a green channel issue.