I am trying to work out how to draw consistently sized cubes when I have multiple three-point perspective systems. I have a cube in one system and I want to draw an identically sized cube in another system. For example, one cube may be facing up and to the left and the other will be flipped to face a different angle. I would like to be able to translate the cube from one perspective to another without any guess work. How can I do this?
In the following image the red and blue cubes are in the perspective system with VPs 1 and the green, black and purple cube is in the system with VPs numbered 2. The circle is the 90 degree cone of vision and the horizontal line is the horizon line. The 45s are 45 degree vanishing points.
I would like a method to allow me to render a cube in perspective 2 that is the same size as a cube I rendered in perspective 1 without guessing the length of a side.