Dobsky perspective question

[nickmarshallvfx]

Hi all,
Quick question from Carl Dobsky's 2 point perspective tutorial that has been bugging me for a while. In the dvd, when Carl is setting up the perspective in full to do some excercises in basic shape placement, he sets up his horizon line and cone of vision with his station point. At this stage he puts in his ground plane. Now, when he places his ground plane, to calculate where the ground plane should lie, he says 'however many feet away we are, we count that number of feet down using our vanishing measure' and then he takes it back up depending on how high off the ground he wants the camera to be. But he never explains in the 'however many feet away we are' what he is talking about. How far away from what?
Ive never figured out exactly what this meant, and so am still a little stumped as to how to accurately work out the placement of the ground plane.

Any help would be appreciated, its the only thing from this awesome series that ive struggled a little with.

Thanks!

[sone_one]

the distance to whatever point you are basing your measurements on. it can be any point on the groundplane basically, but for economical reasons its best that its the point where an objects closest edge meets the ground.

[nickmarshallvfx]

Ah ok, I follow, that makes sense! thanks for that sone_one, I was beginning to think i wasnt going to get a response!