Hi guys im new here and only been using UE4 for a couple of weeks now and really enjoying it but i have run in to a problem with the lighting on static meshes as you can see here:
I have tried creating a second unwrap uvw in a new channel for the lightmapping but the results were a little better but still not correct i had no overlapping UVs in either UV channels as you can see here:
The engine is giving any error after the lighting is built just poor results i have also tried increasing the lightmap resolution to 128 as recommended by the UE4 Docs and i have tried different ways of unwarping the UVs but this
either causes overlapping UVs or the same effect.
Another problem im having is that static meshes that are set to static give poor quality shadows on the environment as well as themselves
Any help or suggestions would really be helpful 
The lightmap resolution is too low, default is 32 which means 32x32 pixels. Bumping that up to 128 isn’t going to help much for something like that. It needs to be like 1024.
Even then, you have the entire model together, which is going to be a problem. You’re going to need to separate out parts of the mesh so that you can use multiple lightmaps and get better detail. The lightmap UV’s need to have a certain amount of space between each UV island or the pixels will bleed across the edges.
As for the environment, the lightmap resolution is too low for that as well. If the shadows ever look blobby, then the lightmap resolution is too low.
Hi Defused,
I’m not sure I’m understanding fully what you’re trying to do with the first part of your question. It looks like you resolved the issue with overlapping UVs but are not getting not getting the shadow resolution you want? I know you said you increased the resolution to 128. What am I not seeing that is the issue?
As for the other problem. You will need to up the lightmap resolution of those objects as well. If it’s landscape terrain it does not need to be a power of two (32, 64, 128). It’s better to adjust it with whole numbers. The default is 1.0. Adjust it to 2 or 3 for better results. The lighting builds will take longer the higher the number. Also make sure you’re using a lightmass importance volume in your scene. This will help keep build times shorter.
If you want softer shadows for your level also make sure to use a Sky Light.
Thanks!
Tim
thanks for the response man ill try out some of your suggestions and let you know thanks 
Hi Tim
after i followed darthviper`s advice on turning up the lightmap to 1024 on the building i have much better looking shadows on it im not sure if this is the correct way to do this but it looks alot nicer i also follow your advise to turn up the landscape shadow quality and it works really well with the sky light thanks for that
One other question if i have a lightmap on a model with non overlapping UVs in UV channel 2 can my diffuse UVs overlap in channel 1? i only ask so i can get much nice looking textures on the model with out using huge texture on the model i have been looking at the UE4 Docs but i wasn’t if the diffuse UVs can overlap if there is a lightmap?
thanks for all your help
Yep, your other UV channels can overlap and whatever you want, though precision grows less (coordinate numbers get too high) if you have something further away from the 1x1 space so don’t make things super huge outside of the bounds.
Ok thanks man i think ill just start again on the all my modeling and go for a more modular approach to things
Just remember that the lightmap covers the entire object, if it doesn’t get enough detail in the lightmap at a high resolution then the object has too many surfaces and needs to be broken up into more than one mesh so that it can use more than one lightmap. In the case of buildings you can get by with a low resolution lightmap on things like a big flat wall or floor since it can use almost the entire lightmap and without seams, but for other complex things you have to have a higher lightmap resolution.
Something else to keep in mind is that this isn’t really the recommended way to build something like this. What we’d do here is create a single wall segment with a window in it and duplicate it 12 times (3 for each side of the room). These meshes can get away with smaller light maps and you’ll have a more flexible mesh set in the end because, hey, you can use that mesh on the second floor now if you like. 