Empty parts in UV textures: How do they influcence the file size?

Especially when unwrapping models consisting of few big parts, it’s not always possible to use all the space properly.
How do those empty (usually transparent or black) areas affect the filesize?
Are they generally to avoid or are they compressed so well (DXT) that it doesn’t really matter?

Fairly simple question really, but I’m curious what experiences you have made with that…

I don’t think it really affects the size. Try using as small of a resolution as possible though.

Generally you want to use as much space as you can in order for the texture to look good.

If I recall, they don’t really change much as far DDS textures, but it really ends up depending on the filetype. gif for instance compresses really well as far as large monocolour zones go.

And well you can easily test it I guess. Make a few example images to compare.

as far as I know it’s basically wasted memory , since it’s loading something that does not affect the end result. It only becomes a real issue.when like half of the texture goes unused tough.

Not very experienced so take it eith a pinch of salt

Hope I’m not just saying the same thing, but essentially any colors used in the VTF file have no real difference. In other words, your files are always going to be the same sizes which strictly depend on how large the texture is rather than what space the actual used parts of the texture take up. Any unused areas still exist in the file, transparent or not. It’s fine to have blank space since it’s pretty much impossible to avoid on complex unwraps but if the more empty space you have, the more room is going to waste.