I was wondering how to reduce the image and material count in a game engine like Unity. If you scale your textures as shown in this lecture it bleeds into another texture in a texture atlas. So how do I see those assets using a texture atlas w/o bleeding?
This is how I am doing
This is how other people do it
Your question is a bit unclear to me.
You can have one bitmap file (texture atlas) and have multiple UV-Maps pointing to that same image. Each mesh island can have a margin to overcome bleeding, but depends on your model and unwrap quality.
You can scale your mesh island to fit the image part
Or are you referring to the new UDIM-Tiles support.
Scale your UVs and move them into place to fit the part of the image you wish to use.