True, but I think the reason you are changing the shape of a muscle is because you are causing certain fibers within the muscle group to hypertrophy faster than others. I guess I should have worded my question a little differently. Do you think you can actually increase the detail of a muscle or the seperation between muscle groups by training or do you think this is just a result of how lean you are?
no
separation and detail are controlled by how lean you are.
the only thing you should be doing with weights is building muscle, which is a hard enough job in itself.
put it this way, say if you had 20% bodyfat and you held a lot of fat in your legs.
do you actually think you are going to have a snowball's chance in hell of adding detail to those legs while still retaining 20% bodyfat?
if, on the other hand, you have fat legs but there wasn't much muscle there anyway and then you started building muscle in the legs, the extra muscle itself could show more shape and detail to your legs.
for every casey viator that went high reps/sets before contests there's a mentzer or yates that didn't.
which bbers were more successful?

casey was only a success whilst with jones. left to his own devices he was not successful.