Im trying to draw objects/scenarios and people outside but i have some basic problems when i try this. The perspective for near objects varies the vanishing point moves when i close one eye and open the other and viceversa... sometimes with one eye i can see the side of the box but if i use the other eye the side dissapears or gets wider (depending on the position of the box). So, should i assume people use the perspective from only one eye when drawing from life? Another one is... what happens if the person moves? I know how to draw a person who is sitting/standing still... but how are you supposed to try this on busy sites like a bus stop, should i like take a gesture drawing of the person and try to memorize the people that is there or what? but then im not drawing from life but from memory. I always listen people that drawing from life is better, but why exactly?, i can understand that its useful for tone and values since you can lose a lot in a photography (specially the red on digital), colors and value... but when im trying to get form and line... is that useful?