Step 1: Create an animation
Start a new project and create a movie clip that has some obvious animation in it. Here, we’ve used a star outline that fades in and then rotates through 90 degrees while fading out more slowly. This has been overlaid on three layers and the keyframes offset.
Step 2: Generate a sprite sheet
In the Library panel, right-click the movie clip and select Generate Sprite Sheet from the context menu. (Note: you can select multiple symbols to generate a sprite sheet from them all.) In the resulting window, the Sprite Sheet and Preview tabs give you a sprite-sheet overview and animation preview, respectively.
Step 3: Define settings
Under Sprite Sheet output, you can define specific image dimensions, the image format, a background colour (transparent by default), and a data format. Look at fine-tuning further options, such as MaxRects in Algorithm, to optimise your work. Click Export when you’re satisfied.