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UV unwrapping questions

Hi guys, sorry if this has been asked before but I can’t find an answer to this one.

I have multiple objects in 3DS MAX, unwrapped, with a second unwrap on UV channel 2 for lightmaps and shaders set up, all working fine. They are also working fine when imported into Unreal. The problem I have is this: Can I take the different geo with different UVs/Materials, combine them in max into one object and then import them into Unreal without causing overlapping UVs? Is this possible?

I ask because I don’t want to import 50 - 60 objects and then re-build my object in Unreal.

If you combine things then you’d need to go into your lightmap UV channel and pack them again so that they aren’t overlapping. It can help performance to have fewer objects but you can only have one lightmap per object so if it’s got a lot of surface area you might not be able to get enough detail in the lighting without increasing the lightmap resolution really high.
If you want some way to get things placed in the same position as they are in 3ds Max you can try the FBX Scene Import option: https://docs.unrealengine.com/latest/INT/Engine/Content/FBX/FullScene/index.html
You can export it all this way and it’ll get the objects into the content browser like normal but it will also allow you to make a Blueprint that contains the locations of all of the objects so you can just drop it into your game and it’ll be set up the same way. If you have instances it will also maintain those (so if you use a chair multiple times then it’ll import the chair by itself into the content browser and then have the instanced copies in the Blueprint).

If you want to optimize things, then you can combine some simple meshes, start first with things that use the same material and are located in the same area, if they have a low poly count then it’s better to combine them with other objects. But again, remember that each object can only have a single lightmap so you can only combine so much until you aren’t able to get enough lighting detail. And you’d still have to repack your lightmap UV’s so that they aren’t overlapping.

Thanks for the info DarthViper.