Splitting Surfaces for Perspective Drawing December 1, 2024 Let’s say that we are hand-drawing a shape with a rectangular surface, e.g. a rectangular cuboid such as this one: And we may wish to add, say, a door somewhere on the right-facing wall. We decide that in our scene, this door is at a certain ratio R $R$ of the distance L $L$ from the near edge to the far edge. But to what ratio r $r$ does…