# 3-D Drawing and Geometry

### by Cathi Sanders

#### A Math Forum Summer Institute Project

1998 Summer Institute || Participant Projects || List of Participants || Sum98 Staff || Agenda

## Perspective Drawing

It is relatively easy to sketch in oblique and in isometric, but there is a third type of drawing that more closely resembles the way we see things in the real world: perspective drawing.

When we look at the world around us, we see objects in perspective, as in this photograph of the Armory Mewata in Calgary, Canada, from McGill University's course, Canadian Architecture 101:

Notice that the lines on this type of drawing are different from those in either isometric or oblique drawings. In this type of perpsective drawing, which is called two-point perspective, there are three types of lines: lines that converge to the left at a point (called the Vanishing Point Left), lines that converge to the right at a point (called the Vanishing Point Right), and vertical lines. The drawing below illustrates these types of lines on the Calgary Armory Building:

When drawing in perspective, you can vary your point of view. This is not true in either isometric or oblique drawings, both of which have a fixed point of view and appearance. Changing the location of the vanishing point will cause a change in the appearance of the perspective drawing.

You can use this JavaSketchpad applet to play with perspective. Drag any of the red points in the drawing.

Then learn about vanishing points by exploring How To Draw in Two-Point Perspective with pencil and paper or using computer software, and One-Point Perspective Drawing.

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