The following is an excerpt from Chris Georgenes’ How to Cheat in Adobe Flash CS6. Fully updated for CS6, How to Cheat in Flash CS6, is a goldmine of artistic inspiration, timesaving practical tips, tricks and step-by-step walkthroughs that you’ll wonder how you survived without it. Here, Chris helps you to create a rotating globe in Flash.
Whenever I work with masks, I feel like a magician. Masks provide the ability for you to create illusions, much like a magician’s “sleight of hand” technique. It’s all about what the viewer doesn’t see and you, as the designer, have the ability to control that. One of the more popular animation requests from Flash users is how to make a rotating globe. The first thought is that a globe is a sphere and to animate anything rotating around a sphere requires either a 3D program or painstaking frame-by-frame animation. Not so if you can use a mask. Remember, it’s not what you see, but rather, what you don’t see.
1 First step is to create the continents. A quick online image search will yield plenty of examples. Import the image into Flash and leave it as a bitmap or use the Trace Bitmap feature or manually trace it using Flash’s drawing tools. Convert it to a symbol.
2 Create a new layer and move it below your continents. Draw a perfect circle using the Oval tool O while holding down the Shift key. Select this circle and copy it, then paste it in place on a new layer above your continents.
3 Mix a radial gradient similar to the one shown and fill the circle in the layer above your continents. Make sure to mix enough alpha into each color so the continents will show through. Using the Gradient Transform tool f, edit your gradient so that the highlight edge is off-center to one side.
4 The next step is to create a mask layer using yet another copy of the circle in the bottom layer. Create a new layer above your continents, paste in place the circle and then convert this layer to a mask layer. This will prevent the continents from being visible outside this circle. All you need to do now is motion tween the continent symbol across this circle.
5 To avoid too much of a delay in the animation between the first and last frames, you can add a new masked layer with a new instance of your continent symbol. The best way to make this looping animation as seamless as possible is to copy the first frame of the continents and paste it in place into the last frame of your Timeline. Then work backwards in the Timeline and position the continents outside of the circle to the right.
6 Since the first frame is exactly the same as the last frame, and each frame in between represents a slightly different position for the continents, select the symbol in the last frame and use the arrow keys to nudge it over a few pixels. This will avoid the two-frame “hesitation” in the movement of the continents every time the playhead returns from the last frame to frame 1.
You can always move your entire animation into a Movie Clip symbol so that it can be easier to position, add multiple globes and/or target with Action Script. To do this, drag across all frames and layers to highlight them in black. Right-click or Command-click over them and select “Copy Frames” from the context menu. Open your Library and create a new Movie Clip symbol. Right-click or Command-click over frame 1 of this new symbol and select “Paste Frames.”
Excerpt from How to Cheat in Adobe Flash CS6: The Art of Design and Animation by Chris Georgenes © 2012 Taylor & Francis Group. All Rights Reserved. How to Cheat in Adobe Flash CS6 can be purchased Amazon.com, BN.com, and wherever fine books can be found.