Blender Lightmap Problems
Hello,I am trying to make meshes in blender and import them to ue4,and some of them end up with weird shadow bleed,I am kinda new to modeling so i probably done something wrong,the thing is,that i saw many videos\posts on this subject and i yet to find a proper answer for my problem,its even harder when most of the detailed tutorials are for Maya,and although i saw them,didn't help me as much as i thought.
Anyway,here are the pictures of the mesh inside Ue4(before and after build):
and in blender (two objects with two different lightmaps and uvs,i tried combining them,but it yields bad results):
Thanks in advance.
asked Feb 17 '16 at 12:19 PM in Rendering
you have way too many uv islands, which wastes most of your texture data on padding, and creates islands thinner than a pixel in lightmap resolution.
break the object down into cylinders and spheres, unwrap each cylinder with a single UV island, and unwrap each sphere with 2 islands, splitting the sphere into top and bottom halfs.
answered Feb 17 '16 at 06:20 PM
The after image didnt open for me. But probably the problem is that the shadow information in the lightmap bleeds out to other faces. That happens when the gap between the uv islands is too small.
You have 2 solutions: - Increase the gap betweern the uv islands in your uv. Then reimport that mesh in unreal and use that uv for lightmap calculations (dont let unreal create a lightmap uv at import) - Increase the lightmap resolution. This one should be used with caution because it affects performance.
You can use a combination of the two methods, until you get a good result.
But, as i have some experience with that, you may get some shadow bleed from time to time. When you get all the scene together, with normal maps and occlusion, its hard to notice the shadow bleed .
Reducing your uv island might do the trick. Like Scott told.
answered Feb 18 '16 at 01:34 PM
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