It also depends on the style you’re trying to draw from your head. For comic book, animation, anime/manga styles, people usually draw out of their heads, but this ability only comes after years of intense study of the underlining structure I mentioned before. What happens is that the artist will build up a collection of memory of how everything looks and functions–in their brain, and when drawing, they simply access that collection of memory and utilize it. This works only up to a certain point–meaning, once the style you’re working in starts to venture further into a more realistic look, the need to use photo reference/life models become stronger and stronger, and this is because reality is just full of too much detail and variations for a human brain to ever really fully memorize. So, someone like Adam Hughes can probably still get by using his memory only, while someone like Tim Bradstreet–well, the word on the street is that he can’t draw anything decent unless he’s tracing photos–that very realistic style comes at a price, apparently. Then you have the really stylized anime/manga stuff, which plays by their own set of established exaggerations, which is universally shared by all artists working in that genre. But even for stylized looks like that, they still sometime use references to simply base poses off of. All those anime/manga pinup pictures–many are obviously based on fashion magazine or celebrity photo poses, or even still frames from movies. Working that way is actually pretty smart, because your poses (underlining structure) are grounded in very effective and natural body language, but the surface is heavily stylized for a different effect. That effect is very similar to those animated gif’s of anime/game characters dancing, and are obviously motion-captured. The opposing dynamic of a very stylized look against very realistic movement creates a certain effect that you won’t get from the typical jerky animation you’d find in anime.
