# At what point does 1 point perspective become 2 point perspective?

I'm trying to imagine a box rotating, and want to be able to draw it without guidelines. Let's just say you're drawing boxes or cubes and you start with 1 point perspective, my problem is when that box or cube is going to have 2 points perspective.

There is no one point perspective or two, There are countless, the point is that the ones you are using are the ones that the parallel sides of a box have.

Take a look at this answer. Finding the possible vanishing points in a landscape

So if you are rotating the base of your cube, just see where the vanishing point is. It is probably very far, outside of your paper, but there it is.

As you rotate the image at some point one of these vanishing points will be parallel, and from that point, a new vanishing point will form.

1. I have a two-point perspective (3 actually but let's forget about it), and I start to rotate the cube.

2. The vanishing points are there but they are also rotating.

3. At some point, one of the vanishing points (red) is sooooooooo far away that looks as it is parallel lines.

4. And it starts to diverge, so the vanishing point starts to form on the other side of those same lines (magenta)

5. And we went back to step 1.

• Just a point about the “so far away it looks parallel”—really, they ARE parallel. If instead of considering an infinite wall in front of you which contains your picture, you consider a glass globe you are in through which you can see your surroundings in all directions—then all parallel lines are great circles, and the vanishing points for any set of parallel lines are the TWO points (on opposite sides of the globe) where those great circles cross. Apr 15, 2019 at 8:39

When you rotate a 1 point perspective box that is parallel to the projection plane (eye or camera) in one axis, it becomes 2 point. However, the smaller the angle of rotation, the less obvious the convergence between parallel lines. At 45 degrees the planes in a cube will mirror each other.

Notice that the cube is intersecting the horizon line at the middle. Otherwise you are dealing with a third vanishing point.