Getting some bizarre artifacting on lightmaps for this static mesh, this is just a lowpoly with flat grey diffuse and a normalmap on it:



I have no idea what is causing this or how to fix it. It isnt happening with other meshes where I used exactly the same process to import and light them. The weirdest thing is when you break the lighting and need to re-bake it ... the weird artifacting is gone and the normalmap starts looking like its actually being rendered.



this is the material


actor properties:

How do your lightmap UVs look? That seems the most probable source of the problem.

lightmap UVs are the same as UV channel 1, 100% unique UVs nothing overlapping - channel 1 textures are 1024x2048 if that matters, UVs are here:

Those UVs are super packed for a lightmap unless you're baking some crazy resolution, also lightmaps are square, so your ratio will be wrong and the vertical gaps will be even smaller. Not sure this is the cause of the problem, but maybe try remaking your UV2s (kinda tricky having something clean considering the geometry of your model), or just baking vertex lighting instead (add a few extra vertical loops if necessary).

Try setting detail mode to high in properties. Also raise lightmap resolution to say 1024 as a test to see if that helps.

What are your shadow settings? Modulate? Normal? I doubt this will help but have you tried flipping the normal map green layer?

Turn off overide lightmap resolution.

I don't know if it's a direct cause but the UV's you have for your lightmaps aren't terribly efficient.

I'd try re-mapping the second channel with fewer UV islands and fewer seams. The fewer seams you have in your lightmap UVs the fewer opportunities for bleeding and splotches you'll have.

Remember lightmaps have no padding. So everywhere you've got seams is black and that will bleed into the lit areas causing blotches.

I've set the detail to high and tried highres lightmaps, didnt make much difference. I'll mess with the lightmap UVs and see what happens. If you look at the original problem though, the artifacting is going right across like 10 different UV shells - I dont think the lightmap UVs are whats causing this. I see that they suck and need to be fixed anyway, but I dont think thats the root of the problem here.

If it's not the lightmap UV's、I can only imagine it's a setting in UDK, or something up with your lights in your scene.

Are you using lightmass? What are your settings in lightmass?

Also, instead of using the lightmap resolution override, have you tried just adjusting it in THAT particular static mesh assets properties window?

At first glance I'd think it's the lightmap UVs, but if you've already tried that...

It might sound strange and it's just a guess, but what about the scale of your mesh? Is it around the same size as a typical UDK prop? Maybe 192 units or so tall? If it's really small then the lightmass settings might have an effect. StaticLightingLevelScale might be something to tweak if that's the case.

Lightmap Coordinates were set to the wrong UV channel in the static mesh editor. I really am a retard sometimes =s

Originally Posted by marks

Lightmap Coordinates were set to the wrong UV channel in the static mesh editor. I really am a retard sometimes =s

It happens to the best of us ^_^