>>996987Vanishing points aren't random, you could make a star thing and glide it over the page or just look for lines that should be parallel in a different perspective but aren't; just make these lines longer and you'll find a place where all those lines meet. That's the vanishing point.
E.g. in picrel, the small table in the front of the couch should have a normal, rectangular surface, but the normally vertical lines aren't perfectly parallel. If you make the lines longer, like the artist did with the lines in that picture, you'll find the vanishing point they meet at. The second vanishing point is so far to the left that it didn't make it onto the picture, but it's still there and if you make the canvas larger, you can find its position as well. Same with that third vanishing point to the right.
