Combining multiple maps into one. How?

Defonten · Jan 2015

Greetings,

I got multiple objects in my Toolbag scene. Each object with it's own set of individual maps (albedo, rougness, metallness, normal and occlusion) Quite a lot of textures I must say. But my client wants all maps to be in one 2K texture file. So my question is how and what is the best way to combine all mentioned maps of all objects into one single texture file?

I can only think of simple combining all objects in my 3D app into one, and importing all textures (albedo, normals etc.) into single photoshop file according to my UV coordinates and place all of them side by side but the problem is that this way I have to downsize maps quite significantly just to have them all fit..

Thanks in advance!

Farfarer · Jan 2015

Yeah that's probably what you'll have to do. Ensure that all of the UVs for the meshes fit into one UV space and then bake the textures over from the original UVs to the new UVs.

For the sake of your normal maps, you will have to ensure that you do not rotate any of the UVs when combining them or you'll have to rebake the normal maps for the new UV set.

If each item is all nicely unwrapped to it's own 0-1 UV space you can just scale the UVs down by half and shift them over by half (or quarter - depends how many items there are... hopefully numbers that play nice). It'll make combining the textures a lot easier as you won't have to bake them over to new UVs - just stack 'em together in Photoshop.

Defonten · Jan 2015

Thanks for the info Farfarer! As long as my "texture budget" is limited to only one 2K map I try to save as much space as possible for albedo and normal maps mostly as obviously they are the ones that initially describe the look of the object. Of course I wouldn't want lowres and blurry textures due to overcrowdedness of different map types in one place. By the way, can I use Alpha channel and put let's say Occlusion or Roughness map in it to free up some valuable RGB space for other color maps thus making them more clear and not overly downsized? Can I use tga format for the final texture or should it be JPG only?

Farfarer · Jan 2015

I don't think they mean a single 2k texture to contain ALL the maps. I would think a 2k diffuse, a 2k normal, a 2k material (spec, roughness, ao, metalness). Essentially have all the items on a single UV sheet.

And never use JPG for textures. Ever. It's a lossy format. Use TGA/TIFF/BMP/PNG... just not JPG.

Defonten · Jan 2015

Hmm.. indeed, I think that's what I'm supposed to do. Any thoughts on placing ao map into alpha channel? Is it acceptable?

Thanks!

EarthQuake · Jan 2015

I can't see any possible reason why you would need to pack all different textures, including diffuse, normal, roughness, etc into one image. This makes literally no sense, and means that you would need a separate UV layout for each map type, and a special shader that used a unique uv layout per texture input. This simply isn't something that anyone does or would ask someone else to do.

I would suggest talking to your client a bit more to clear it up as there seems to be some miscommunication here. Asking questions isn't a bad thing.

Various maps can be packed into both alpha channels and individual RGB channels. Your client probably has a specific way they expect the channels to be packed, so again, you should ask them to clarify.

Defonten · Jan 2015

Earthquake, you're absolutely right. I too think it would be a bit overcomplicated.. I should definitely ask them about it. Thanks a lot!

Combining multiple maps into one. How?

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