Working with decals

Count Vader

I have a scene that needs a shit-ton of decals in it, so I was just wondering , rather than saving each one out individually is there a way to create a 'texture' atlas that where the individual decals reference a certain area of it? Or does Unreal not support UV's for decal materials?

Also, is there a way to get decals to affect only one texture channel? Ie if i only want a decal that affects the normals of the underlying surface, but not the color or roughness, etc

I know a lot of this was addressed in this thread http://polycount.com/discussion/155894/decal-technique-from-star-citizen/p1 but that has to do more with placing 'floater' planes and then creating a tri-planar projection material to handle relationship with underlying surface, but that tends to screw with the lightmaps when you build lighting.

Obscura

There is a way to use decal atlas. You just need a special material setup, similar to what you'd use with a simple texture atlas. You need x-y coordinate paramater that can be used to which part of the atlas you want to use. After that, you can create some material instances, for the different mappings. 

Yes, there are some decal modes to affect only specific channels, ie normals. 

Search for an atlas texture material setup, and check out the decal doc in the UE4 documentation.

Count Vader

Ahh ok, I didn't realize a regular texture atlas required a special material set-up (i've never actually used one before lol) I assumed people just placed UV's for whatever objects onto that part of the atlas, thought obviously that doesn't make any sense for larger/more complex models lol.

Is this what you were referring to as far the UE4 documentation? https://docs.unrealengine.com/latest/INT/Resources/ContentExamples/Decals/1_2/index.html I guess the DBuffer decals is what I'm after?

Obscura

Yes