Does the size of the UVs in the Lightmap channel matter?
I had some objects in Maya that I would like to act as one object in UE4, so I exported everything in a single FBX and imported it with the combine objects option checked. But it seems that it really does make it into a single object (I expected it to be working like a 'group') and combines all the different Lightmap maps of the objects into a single Lightmap thus making UV overlap and cause strange artifacts. So I went into the Lightmap channel simultaneously in every object and lay'd out all the UV in the object into really small pieces. Is this a bad thing to do? Does it affect the effectiveness of the lightmap resolution etc?
Depends on the complexity of the object you are working with, but most of the time it is best to keep things as simple as possible. For instance, you can combine a whole house into a single mesh and prepare it's UV's in Maya but you'll run into problems like light and shadow bleeding even with high res. lightmaps because the UV layout is going to have too many islands from different parts of the house. So it's up to you to test and see if it works or not.
answered May 01 '14 at 12:34 AM
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