Light map questions
polycounter lvl 14
Light maps seem to be an under focused area of talk. I've asked multiple times about them and been linked multiple times to the Unreal documentation. I continue to have issues, namely having them mipmapping down to bad quality. Usually by raising the light map resolution I can take care of the issue, but then moving away from the object causes artifacts to appear. Can I stop the mipping on lightmaps? I asked somewhere outside of polycount at one point and was again linked to Unreal documentation on the subject, but it didn't have any instructions as to how I can fix it. Also, is it necessary to place the UVs in a perfect square-snapping type placement? Is not doing so whats causing the issues possibly? How important is it to have pieces connected in the UVs, or to be flat, as opposed to at an angle? thanks
Replies
But.... You should be able to tell the render system how much mips levels should be use per material.
For example. Vegetation with alpha maps suffer from mip levels. So we normally force to load 2 or 3 mip levels only. Since we use the DDS format, we just export the texture with 2 or 3 mips only.
In Unreal you should be able to do something similar to this. Or by forcing the shader, or manually exporting the mips.
It sounds like you're seeing bleeding around the UV edges maybe? Add some padding.
You can also bias the mipping distance, so it holds onto the highest mip longer.
Disabling mipping is going to hurt your rendering performance, so not really a good idea.
I'm guessing that's the solution. I'm experimenting with various UV layouts when things don't render correctly with the light maps. Sometimes there is a thin poly that needs to be stretched out in the 2nd UV layout.
How do you do this in Unreal 4? Also, Can I adjust the LOD groups settings all at once? As opposed to going in to all of them individually?
Thanks