I'm at the UV unwrapping stage of a model, and I've added a bunch of texture seams such that when I perform the automatic UV unwrap, the resulting UVs give me fairly consistent texel density across the model while making pretty efficient use of the texture.
However, the consistent texel density is less than ideal; there are many parts of my model which could benefit from a higher texel density, and other parts where it needs comparatively very little texel density (for example, surfaces that are rarely visible and not looked at closely). It would also be nice if I could give a density boost to sets of polygons within a part of it without breaking it into a separate island or introducing a texture seam (for example, on my character's face).
Is there any way to indicate to Blender that certain faces need more or less detail on average, so that the automated UV unwrap can automatically scale the respective islands (or even faces within the islands) up and down as appropriate?
Alternatively, is there a plugin where I can simply scale the already-unwrapped islands up and down myself and then have it automatically repack the islands without otherwise modifying them? This would be less ideal but it would still save me a lot of work.