Animating Depth: Tweening Movement - Flash 3D: Animation, Interactivity, and Games - page 87

Exercise 3.5: Using Trucking to Simulate Depth in Flash
Step 1: Getting started
Open the file 3_6_depthIllusion.fla in the Chapter 3 folder on the accompanying
CD. This exercise pushes movement along the z-axis further. Scaling an image larger
to simulate camera movement creates a minimal illusion of depth. What happens if we
scale multiple layers as when we create parallax scrolling? A much greater sense of
depth is achieved (Figure 3.49).
Figure 3.49 Truck in using multiple layers to simulate depth
The Timeline contains four layers: sky, background, middleground, and fore-
ground . The artwork on each layer is an instance of a movie clip. The imagery was
created in Photoshop and saved as a PNG file to retain the alpha channel. With the
exception of the sky, all other images were built larger than the Stage size. Why?
The artwork needs to be scaled to simulate a camera trucking in. Bitmap images are
resolution-dependent. This means that the pixels will become more noticeable as the
image dimensions are increased. To correct this, the artwork was created at the largest
size possible. After being imported into Flash, each image was scaled down to create
the composition on frame 1. Scaling down a bitmap image doesn't create pixellation as
scaling it up does. The foreground image was scaled at 55%. Both the middle ground
and background images are at 50% of their original size.