Blender 3D: Noob to Pro/Perspective Views

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So now you know how to simulate 3D using isometric projections. By now, I'm sure you're hungering for a way to do 3D for real. There are several approaches to drawing in perspective. These are one-point perspective, two-point perspective, and three-point perspective. Each of these points refers to a vanishing point.

[edit] One-point perspective

This is the kind of perspective that you use if you are facing an object head-on and staring right at the middle of it.

Imagine looking down a straight set of train tracks. The tracks will appear to converge at some point on the horizon. This is the vanishing point.

One-point perspective is the easiest to draw. Suppose you want to draw a cube. First put a single dot in the middle of the page: your vanishing point. Now extend lines out from the vanishing point, at each of the 4 diagonals. Draw 2 squares, one "inside" the other, so that all 8 corners lie on these 4 lines. Now connect all corresponding corners and you have a cube.

You can see that some of the lines in this cube are parallel, and some converge. Specifically, the left-right lines are parallel, the up-down lines are parallel, but the in-out lines converge. Since this is one-point perspective, there is only one point of convergence, right in the middle.

[edit] Two-point perspective

But what if you're looking at the corner of something? Say the corner of a large department store that extends for a couple blocks. Now what? You can't use one-point perspective. Here, you must use two-point perspective. This requires two vanishing points, usually to the left and right. Draw the corner of the building as a vertical line, and then extend the lines toward the vanishing points.

In the diagram, you can see that the up-down lines are still parallel, but now there are two sets of lines that converge: the four left-right lines converge off to the right, and the four in-out lines converge off to the left.

[edit] 3-Point Perspective

Now here's the rub: you're looking down on that same building from a rooftop across the street. Now what? Three-point perspective, or the kind you actually see in reality. Here, you draw three vanishing points: left, right and up. Proceed drawing lines as with two-point perspective, but this time the sides of the building towards the distance will not be drawn straight up, but towards the vertical vanishing point. In this case, since you are looking down at the department store, the vertical vanishing point will be below the left and right points.

In this case, there are no longer any lines which appear parallel. The 4 up-down lines, the 4 left-right lines, and the 4 in-out lines all have their very own vanishing points that they converge to.

All of these are a pain to draw. Enter Blender, a program that will do it for you, provided you give it information about each side of an object (orthographic projections), and a shape that makes sense in perspective and isometric views. All these will become routine in getting to know Blender.