It looks like you have drawn the side of the box instead of the front. As the boxes rotate further away from the viewer the front plane of the box will appear to shrink and youll see more of the side of the box until it becomes a straight line on the sides. You only need one vanishing point (this is from my experience), and thats the middle VP, but it can guide. I suggest you find a reference (google rotating box drawing exercise) because Im sure I have got some thing wrong, and its very hard to imagine it. Hope that helps.
KDee14 in the post "I dont understand how Im supposed to use the second vanishing point in the rotated boxes exercise, how am I supposed to know where they will end up?"
2022-06-22 12:04
It looks like you have drawn the side of the box instead of the front. As the boxes rotate further away from the viewer the front plane of the box will appear to shrink and youll see more of the side of the box until it becomes a straight line on the sides. You only need one vanishing point (this is from my experience), and thats the middle VP, but it can guide. I suggest you find a reference (google rotating box drawing exercise) because Im sure I have got some thing wrong, and its very hard to imagine it. Hope that helps.