How to Mask Offstage Characters in Flash Player

If you create a movie clip in Flash to load another movie clip that will move a character from offstage onto the stage, but have trouble making the character stay offstage, you can fix the problem. Flash's masking features provide the remedy.

Difficulty: Moderately Challenging

Instructions

1. Open your original animation and select every frame in the timeline. Choose "Copy Frames" from the Edit Menu Timeline submenu.

2. Create a new Flash file the same dimensions as the original animation. Draw a rectangle the size of the stage. Add a new layer. Press the "Option/Alt" key down and drag a copy of the rectangle to the new layer.

3. Lock the top layer. Select the rectangle on the bottom layer and convert it to a symbol (press the "F8" key). Choose "Movie Clip" for the symbol properties. Double click on the movie clip to enter the symbol timeline.

4. Delete the rectangle (you don't need it anymore). Select the frame and choose "Paste Frames." The timeline will expand to fit the contents of the pasted movie layers.

5. Return to the main timeline. Unlock the top layer. Right click on the layer (Hold down the "Command" key and click with Mac OS) and choose "Mask" from the Properties drop-down menu. Load your movie file into any other movie and any offstage characters will be masked.

Tips & Warnings

• The phantom character phenomenon occurs because a movie clip calling another movie clip doesn't know the boundaries of the second movie and expands the stage to include every character.
• Mask your animation as a movie clip because Flash masking layers only mask the layer immediately underneath.