Animating Depth: Tweening Movement - Flash 3D: Animation, Interactivity, and Games - page 81

Step 17: Reveal the middleground layer
Close the movie clip's Timeline by clicking on Scene 1 in the top-left corner of the
Timeline. On the root Timeline, hide the background layer and turn on the middle-
ground layer. This layer contains a larger pine tree.
This larger tree is an instance of the same symbol used in the background. Symbols
help reduce the final file size of your document. Figure 3.41 illustrates how the tree was
altered. The symbol was scaled 200% in the Transform panel. The scaling doesn't affect
the quality of the image, since vector art is resolution-independent.
The color was darkened to reflect atmospheric perspective. Due to lighting conditions,
objects closer to us will appear darker than objects further away. Technically, this was
accomplished by selecting the movie clip instance and changing the Brightness value in
the Properties panel from 100% to -30%.
Figure 3.41 Tree symbol properties for the middleground layer
Step 18: Animate the middleground layer
Let's see how much you have learned. The animation technique is the same as before.
The only difference is the number of frames used for the scrolling movement. Instead
of using 60 frames to complete its cycle, use 40 frames. Reducing the number of
frames in between two key frames will speed up the animation.
This will reinforce the parallax motion. Objects closer to the viewer's perspective will
appear to move faster than objects further away. Figure 3.42 summarizes the artwork
preparation for the middle ground. Don't forget to correct for the slight pause in the
animation. Refer to step 16 to see how to correct this. When you are done, save and
test the movie.