Depth Cues: Creating the Illusion of Depth - Flash 3D: Animation, Interactivity, and Games - page 17

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Depth Cues:
Creating the Illusion of Depth
The illusion of depth can be illustrated within a two-dimensional space. The key words
here are illusion and illustrated . Whether you are drawing on a piece of paper or paint-
ing pixels on a computer screen, you are working with two physical dimensions: height
and width. Depth is the third dimension. However, you can't reach into the computer
screen or extend objects in front of it. You can look only at the flat picture being pro-
jected.
So if there is no actual depth in the image, how do we simulate three-dimensional
space? The answer is right in front of us. We start with our perception of depth and
the visual cues found in the real world. Artists throughout the centuries have relied
on their depth perception to vividly construct three-dimensional worlds on two-
dimensional surfaces.
This chapter focuses on depth perception and how to reproduce it through visual cues.
When you have finished reading the chapter, you will be able to
• Describe how our eyes perceive distance
• List visual cues that create the illusion of depth
• Reproduce depth cues in Flash
Depth Perception
Take a moment to look at the environment around you. What do you see? You see
a world in three dimensions. Now focus on an object that is close to you. Your mind
tells you how far the object is from you, the space it occupies in front of or behind
something else, and its three-dimensional shape. What makes this incredible is that our
eyes are producing only two-dimensional images. It is the human brain that assembles
each image and extrapolates the depth.