Light seams on my meshes

special821

Hey,

So I've been having this problem since I started this project of mine, all my meshes seem to have light seams, shadows where there shouldn't be and I'm getting tired of trying at this, so I hope someone can help me!



I've tried raising the lightmap resolution, wich seems to reduce the problem(still there though) but I don't want to have 256 for every tree, or it's going to get really long to build the light... I also tried redoing the lightmaps, but this only seems to move the problem to the new seam, thus not being of any kind helping...

I really have no idea what could be wrong. All meshes have a custom lighting material, wich isn't the problem either as I tried lighting with phong and still had the same result.

Hope someone has a clue what's going on!

P.S.: Feel free to ask for a shader, lightmap or any screenshot if needed, I'll be glad to provide them!

Thanks,
Phil

LoTekK

What do your lightmap UVs look like?

special821

They're very simple, no overlapping, evrything has room to breathe;



Well... I guess they could be more spaced out, but it's the third time I did those... when I've fixed the prolem I'll make better uvs

chrisradsby

Is the model welded together properly? smoothing groups/hard/soft edges?

special821

Yup, just checked and everything is smoothed correctly, I only have two smoothing groups, one for the cone part of the leaves and the trunk and the other for the underside of the leaves(cones) unless the SGs got messed up when I imported in UDK, it should be alright.

Also, every vertex is correctly welded, there are no holes in the model(except those I want)

I'll have to check in UDK if my SGs are ok, but I'll do that tomorrow.

sinistergfx

You definitely need to space them out more. At that resolution you are sharing pixels between the UV islands (try UV mapping with a 32x32 noise texture).

Straight from UDN: "Padding between UV charts is necessary to prevent bleeding artifacts. Padding around the edges of the lightmap UV layout, however, is not necessary as Lightmass automatically pads around the edges by enough to prevent bleeding artifcats. Note when you are setting up padding between UV charts that 4 texels are usually required to avoid all bleeding, as DXT compression operates on 4x4 texel blocks.

This means that for a lightmap resolution of 32, the padding between the UV charts should be 12.5% of the entire UV space."

special821

.... well, I guess I didn't read it thouroughly. I don't recall reading about a 4 texel padding space between uvs... oh well, I'll do as you suggested and post the results!

special821

So. I'm still experiencing light issues even though I spaced out everything in my uvs;





The lightmap UVs are spaced so that a 64 texel resolution would have at least 4 texels between each uv island. But I don't think UV's are the problem as my other tree also has problems;



Those UVs were generated in UDK with the "Generate unique UVs" option;



Although they look packed a bit...

special821

So, I repacked the UVs of my second tree, but it just moved the light problem.... could my problem be my light setup? I have a dominant directional light(basically the sun) and I have 8 other directional lights, wich basically give me the soft shadow color (to simulate light emitted by the rest of the sky). I'll experiment with other light setups and let you know how it turns out.

In case it wasn't obvious from my screencaps, I'm going for more of a cel-shaded look on this, so basically, I don't want shadows to fade, there either is or isn't shadow, no fading.

special821

Okay, so I tried playing with my lights. I removed all but the dominant directional and got this;



No seams, no problems.... except the fact that I have incredibly black shadows... wich sucks

I still don't know what causes the seams, it looks like part of the mesh is getting an other light, wich seems a bit yellow. See below;



Anywho, I guess I'll eventually find the solution!