When I did the room thumbnail assignment I literally couldn't stop "zooming in" or "zooming out" objects in my thumbnails and realised this puzzled me. A lot. I doggedly triedto force a chair in a room to remain as small as in my simple, 45-angle 2 point perspective version where the horizon line was in the middle. It was impossible without ruining the perspective logic. As soon as I lowered the horizon line, the chair NEEDED to become huge. My drawings came out structurally sound but I was annoyed that I couldn't explain WHY that "zoom" had to happen. I have never questioned or pondered on perspective until this course, I just learned it by drawing a lot and sticking to the "rules" without considering why they work like they do beyond horizon lines and three vanishing points. Watching this video, I suspect it has something to do with static vanishing points, because if the frame around the drawing remains the same size and aspect, vanishing points cannot be moved anywhere and that distorts objects in the drawing.

Great Video thanks Oh, I thought this was Marshall's Perspective Course. Marshalls Perspective on Perspective as mentioned in The Draftsmen? :(

Is that an architectural 3D model of the basilica sancti petri my beloved ᴬᵇᵃⁿᵈᵒⁿ ʳᵒᵒᵐˢ ᶜʰᵒᵒˢᵉ ᶜʰᵘʳᶜʰᶦᵗᵉᶜᵗᵘʳᵉ