How does it look from your standpoint?

Well, it's been a while. I apologize for that.
You may have heard me say that everything is "situational" in perspective. That's my weak way of expressing that, if you move where you're standing--your station point--a short distance in any direction, your view of the world changes. A lot, sometimes. If, before you moved, you were halfway done drawing what lay in front of you, after you moved, you would have to either return to your original station point or redo. The way the world looks is dependent on where you stand.

One example I used of this effect was the challenges facing the matte painter in pre-digital Hollywood. If he or she wasn't precise about matching the horizon and vanishing points of the painting to the film footage, the result would risk not fooling the eye. Above is an example from The Art of The Empire Strikes Back, painted by Ralph McQuarrie himself. You can see, in the first jpeg, the painting alone. The second shows a frame of composited footage. Comparing, you can see that the lower part of the Millennium Falcon was actually a physical set--with live steam, no less. Only the upper part was painted. Talk about an exact match.

How about this European sidewalk artist, Julian Beever? This is a better demo, I think, of the primacy of station point. Note that, seen from the wrong end, Beever's work is wildly distorted, almost unidentifiable.
But seen from the planned-for station point, the art creates a dizzying illusion. How does he know how to distort the art so that it looks right from the station point? That question imagines the cart before the horse. It's not about abstruse calculations. The station point is wherever he set up his digital projector, evidently at about waist level, the night before. Projecting a sketch of the piece, he presumably creates a simplified, paint-by-numbers outline of it, on the sidewalk, under cover of night. Or so I assume. Call me a cynic.

JH