Adjacent static mesh edges shadows

McGreed

I got a bunch of static meshes which is next to each another (see the image), and get this problem with shadows baking problem where the edges meet. Do I need to weld everything together? Would really like to avoid that, because I wanted to keep meshes as instances.

Any ideas how to avoid this?

Ben Apuna

Is the geometry on the edge of those static meshes just a edge or is it a corner? with more geometry we aren't supposed to see?

If there's more geometry "around the corner" of those edges where the shadows appear then you need to split the light map UVs along those edges and make sure there's enough texture padding between the UV shells/islands.

I hope that helps.

McGreed

@Ben
If I move the railings apart, the ends are open, if that's what you mean? So the two railing edges meet up together, vertex to vertex.

Xendance

Afaik there's no real fix to this. You could try using production quality lighting build, or just hiding the seam with some decorative pillar etc.

McGreed

Hmm, guess I have to weld them into larger sections then. cheers.

Ben Apuna

It really looks like an issue with your light map UV layout, sort of like shadows from one area on the light map are bleeding into other areas. Are you sure you've got at least a 2 pixel padding between all UV shells in you light map UVs? (4 pixels between each shell).

If it's not that, then I'm wondering if it's an Ambient Occlusion rendering error.

Try disabling AO in View -> World Properties -> WorldInfo -> Default Post Process Settings -> Allow Ambient Occlusion, then rebuild the lighting.

EDIT:

Here's a excerpt from a post I made a while ago on light map UVs just in case you need it.

Ben Apuna wrote: »

...

Making light map UV sets can be a pain. I've found a good way to start on them is to do your regular unwrap first then duplicate that one and edit the duplicate to get what you need. Usually all it takes at that point is some merging of a few shells, separating others, and re-laying them out so they all get some unique space with enough padding between each other.

Here's some light mapping tutorials that go over the how and why of the process:

http://stephenjameson.com/tutorials/lightmap-uvs-tutorial/
- Keep in mind this tutorial was made for UT3, now with UDK you don't need padding around the outer edge of 0-1 UV space, you only need padding between each UV shell.

http://www.hourences.com/book/tutorialsue3lightmap.htm

http://udn.epicgames.com/Three/LightMapUnwrapping.html

...

MRico

McGreed, did you ever get this issue fixed? I'm struggling with the same issue =(

McGreed

Kinda, it seemed to be a problem with uv padding and shadow maps. When your uv islands were too close, because the shadows map resolution was so low, it bleeded into the adjacent islands edges. So the solution were to scale the padding and/or increase the shadowmap resolution. Though I do consider making something to cover the seam instead, might be more resource-wise, just to avoid increasing the shadow maps. Might do it anyway.