Functional Design

[Pubic Enemy]

But again, if we are just talking about basic drawing stuff, my point is that knowing stuff like that might help, but it wouldn't enable you to draw cloth or anything else.

This is a good point. If having a functional understanding of something was enough to enable one to draw it, doctors would be able to draw good figures and mechanics would be able to draw great tractors with minimal effort. SOME functional understanding is needed, especially for creating new designs, but there is some basic drawing ability that's more important.