Quick question, is it possible to layer clothing as to have a muscle definition texture underneath and clothing above? I looked it up on the forum, but ran into a post from 2016 that I didn’t have access to
If someone could link me some resources, or give me an answer, maybe a way to do it, I’d really appreciate it, thank you 
Do you mean creating something like this?
Or making something like a transparent shirt to see muscles underneath?
No, I mean like, having a muscle mass texture underneath the shirt that’s not visible if it’s covered by clothing, only in the forearms would it show.
Is that possible, to have default textures under clothing without making unique pants and shirt for every type of muscle definition?
if you mean being able to wear 2 types of shirts/pants at once (one for muscles and one for the clothing) then no that’s not possible.
but to make a shirt like that with short sleeves and muscle textures on the forearms wouldn’t be too hard! what i’d do is make a full muscle texture first using a transparent slightly gray-ish shade so it would work with all skin tones, then make whatever shirts you wanted and just put them a layer over the muscles in whatever program you’re using (this way you’ll be able to see the muscles wherever the clothing isn’t covering, but it won’t show through the clothes). after that just save it to your computer as a png so it’s one layer, then you’ll be able to upload it.
Do you know if that would that be bad for performance? Having three or four variations of a clothing type for each type of muscle tone?