Lightmap 2nd UV Channel(UT3)

ajr2764

Hey guys. Im just finding out about how to crete a 2nd set of uvs where there is no overlap for use for lightmapping a static mesh. My question is what rules apply to laying that 2nd set out? I posted below the normal set of uvs where I use overlap, 2nd uv set where I isolated all the uv shells but havent yet got them in 0 to 1 space, and then I scaled it all down and fitted them. Does the amount of space they take up in the lightmap set matter, or is it just determined by the lightmap res set in the engine?

Thanks.

Normal Set of UV's


Lightmap Set, not mapped yet


Lightmap set, mapped

Ben Apuna

The main point is you want to keep at least 4 pixels in between each shell to avoid bleeding from one shell to another. If you are using UDK with lightmass you don't need to leave any border pixels along the edge of 0-1 UV space.

Here's a pretty good tutorial on the subject, it was made with UT3 in mind though so it's slightly dated.

http://stephenjameson.com/tutorials/lightmap-uvs-tutorial/

Also more info from UDN about mirroring and padding.

ajr2764

Thanks, I'll have a look at that.