this R32 thumbnail is a rapid-fire sketch derived from a model. it lacks detail and finesse and exists as a quick visualization for an angle.
were i to take it further, i'd look at the model again with greater scrutiny, possibly photographing it for maximum clarity of accuracy when drawing it.
as far as i can see, tracing a photograph or eyeballing it would render nearly the same results. except the former would save time under a deadline.