I am working on an asset in which I want to use all the 8 UV channels available.
Channels 0 to 6 for Texture UVs, and channel 7 for Lightmaps.
However I encountered the following problem:
When I import the mesh, with the default settings (Generate Lightmap UVs checked), Unreal creates the lightmapUV and stores it in UV Channel 7, as expected.
But I was getting UV overlap errors when building the light, so I discovered that the problem was that the “Light Map Coordinate Index” was set to “3”, instead of “7”, and I am not able to change it anything beyond 3. I mean the slider is programmed so that you can only choose 0, 1, 2 or 3.
So basically, you cannot use the Lightmap UV stored in channel 7.
Is this a bug? or is it by design?
I am missing something?
The work around I found was to use the Channel 0 for the lightmap, and channels 1 to 7 for the texture UVs.
Setting the “Destination Lightmap Index” to 0, and the “Lightmap Coordinate index” also to 0.
I was able to Build the light successfully this way, but I am not sure if this is a good practice, and it is annoying having to do this to all the meshes I import. I don’t see any reason why to put a limit to the “Lightmap Coordinate index”