Learning to Draw: Chapter 3

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Index of Chapter 3: Perspective

1. 3D Images in 2D Media
2. Orthographic Pictures
3. Realistic Perspective

Chapter 3 - Perspective

To make good artwork it's not necessary to draw realistic pictures, but the knowledge is important to allow the artist to express her or his ideas more easily.

3.1 - 3D Images in 2D Media

Paper is a 2D medium, as is most of the media used today, including the television and computer monitors. To correctly represent a 3D object on paper you'll have to draw the object's "3D-to-2D projection". There're basically two kinds of projection, the orthographic and the perspective. The orthographic projection disregards the distortion caused by the distance:

All objects seem to be at the same distance from the viewer, although a side view shows it's not true. The most distant side of a cube will appear to be as wide as the closer one:

The perspective projection makes more distant objects seem smaller than closer ones:

Now, the most distant side of the cube will appear to be smaller than the closer one:

Both orthographic and perspective drawings have their use. Artistic pictures commonly use the perspective vision, but not exclusively.

The 3D space may be represented with three axes:

The "X" axis is the horizontal axis. The "Y" axis is the vertical axis, perpendicular to the "X" axis. The "Z" axis is perpendicular to both "X" and "Y" axes, coming straight from the screen to the viewer (Cartesian system) or going from the viewer to the screen (standard used by some graphic programs).

3.2 - Orthographic Pictures

Orthographic drawings are mainly used in technical material, like building schemes and engineering designs. To draw in orthographic projection, use only parallel lines:

3.3 - Realistic Perspective

Perspective drawings are oriented by convergence points. There may be up to three convergence points. Realistic drawings use three convergence points, but you can disregard some of them, using parallel lines instead (yellow in the following figure), depending on the distance from the viewer to the object and the object's proportions:

Some convergence points may be out of sight. If they are "far enough" from the object, their guiding lines may be considered to be parallel (the first and the second cases of the previous figure), but there'll be always some "loss of reality":

When all three convergence points are far enough, the approximation with parallel lines results the orthographic perspective.

Perspective drawing can be learned by observations and by geometrical study. Let's begin with the geometrical study:

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Page last modified on 1997-April-9 Wednesday.

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