3ds Max 2017: Modify texture and UV map?

[Anonymous]

I've got a model that I've cut into two halves that originally had a single UV map. The system I plan to use the model with only supports textures of a certain size, and so I'm trying to edit the UV map for each half to only include the portions of the old UV map that are relevant to them, effectively giving myself twice the texture size for each.

So to my question: Is there any way for me to edit the UV map, and have the texture be edited along with it?

For example, turning this:

into this:

while keeping the texture underneath intact?

[Swordslayer]

Yes, add the new unwrap modifier with a different channel to the textured object and use that channel in Render To Texture dialog (Use Existing Channel). After rendering the diffuse map to your target resolution (see the saved file, in the render window, shadows are displayed), you can use it with that mapping.