Here's my scenario, I'm sure it's nothing new. I come up with a concept for a figure drawing. I draw it to the best of my ability using construction and all the anatomical knowledge I possess. Then I try to find reference to improve it, both photo searches and mirror work. You never find ideal reference this way and I usually end up taking information from a few different photos. From all of this I can usually come up with a pretty solid line drawing. The problem comes when I want to take it to the next level with a full rendering. My photos will all have unique, inconsistent lighting, so I can't count on them. I try to render with my knowledge of how light works as with cylinders and boxes and such, but that leaves out all the quirky little shadows and highlights that really show the anatomy underneath. I simply don't have the knowledge to fill in the blanks at this stage.
My question is, will I eventually acquire this ability over years of study of anatomy and drawing from life and reference? Or is the only practical solution to hire a model and shoot that ideal reference?
I know that when I draw from reference or life that I have usually allowed myself to be so focused on drawing what I see that I am not really questioning what I'm seeing. I know I need to get better at asking myself; what bone or muscle is causing that shadow or highlight? I know that if I do this I will get better at rendering anatomy from knowledge, but I need someone to tell me if that will ever be enough or is anatomy just too complicated to expect to be able to do this from knowledge alone.