Drawing in Two Stages: Optical and Conceptual

A short video briefly discussing breaking drawing into two stages, optical and conceptual. (A third stage, rendering, would involve actually turning form and shading...adding all the values. When drawing for a painting, the rendering stage IS the painting stage)

I'd like to start uploading more of these short, topical videos. What do you think? Did you find this information interesting or helpful? Let me know in the comments.