Seams on lightmaps

[maxivz]

Im facing this issue with my modular wall followed a lot of tutorials on how to fix the seams and they are still there
Heres a screenshot of how is looks, normals are all ok, lightmap uvs have been made following a grid of 32 pixels, so the uv map wont end inbetween a pixel and break the light, smothing groups all ok, well, no clue what the problem is


Thanks for your attention

Edit: after trying different solutions i was able to lower the seams, but i need to completelly remove them

[Odedge]

Can you psot a screenshot of your UV layout?

[Graylord]

Setting your UVs up to a 32 pixel grid doesn't really mean anything in uvmapping terms. UVmaps have no relation to pixels or resolution.

For lightmaps all you really need is that they do not overlap in any way.

[maxivz]

Heres a screenie of the lightmap uvs in UDK

[Graylord]

Those thin lines, Are those thin faces like that or are they just faces rendered from the side? If they are, there's no room for lightmapping on them and they will cause issues.

Are they the surfaces you are having problem with?

[maxivz]

They are tiny faces like that, and are rendered from a front view, so there should not be a problem there, the issue is in the big left parts

[rowan_moss]

make sure smoothing groups are set up properly in max

if that doesn't work, try making the UV islands smaller and give them more space around them and not so close to the edge, lightmaps seem to be completely random as to whether or not they work :P

[Graylord]

Hmm, there should be enough space there. You may have to increase the lighmap resolution.

[maxivz]

Already tried with up to 512, and the results were:
16: really bad results
32 :same as 16
64: a bit better
128: better, but still got seams
256: bad results
512: even worse results

[benfranke]

Have a look at this: http://udn.epicgames.com/Three/LightMapUnwrapping.html , especially look at the example with the boxes on the bottom of the page.

Is there a reason you're splitting a flat surface up like that instead of just using a large continuous plane? If there is, you might have to unwrap your lightmapchannel by hand instead of relying on UDK like shown in the last example.

Planar faces should always be joined together in the lightmap UV Map, if you split them up like you do right now you pretty much always end up with dark spots in unwanted places.

[Odedge]

Are you sure the static mesh is using the correct UV map in the static mesh editor?

From my experience with similar walls, I found best results when the UV light map islands were connected as much as possible. Also, they should be joined in the same way that the actual faces on the mesh are joined.

while it's good you have some space in between the "islands" (which is what they are called in Blender), you are wasting a lot of space. You can increase the scale of the faces that will be seen, which will produce better light maps.

Here is a picture of one of my walls in game...



Here is another wall (same shapes and all). The other side has a recessed brick section.



Here is the layout of the lightmap UVs...


The red parts are the brick sections for the short version of the wall. The bottom and sides of the walls (which are never seen) are the small faces on the right of the image. I used most of the positive UV space and connected the faces to match how they are on the actual mesh.