Task: Using Onion Skin to Help Create an Animation
Start a new file and set Frame View to Large.
Turn on Onion Skin. Notice that the Start and End Onion Skin markers cannot be moved beyond the beginning or end of your animation (because it's only one frame long at this point). See the Onion Skin markers in Figure 7.6.
Figure 7.6 The Onion Skin markers indicate how many frames are included in the Onion Skin view.
Draw a stick man similar to the way we did in the previous exercise (using only lines).
In frame 2, select Insert, Keyframe (or press F6). This copies what was in the previous frame and pastes it into the new keyframe.
While editing frame 2 (the red current frame marker should be in frame 2), drag the end of one leg to move it to a different angle. This time, the position of the leg from frame 1 is visible (though dimly) even though we can only edit the contents of frame 2.
In frame 3, insert another keyframe. When you move the leg, you can judge how much based on the position of the leg in frame 2.
Continue to insert keyframes one at a time. Make an edit to each new frame, then select Insert Keyframe again.
When you have several frames, you can experiment with changing both the Start and End Onion Skin markers. By default, the markers are set to Onion 2, meaning you can see two frames ahead and two behind. I rarely use the End Onion Skin marker at allI just position it at the current frame marker. I would rather see where I've been than where I'm headed. You can move the markers to several preset positions from the Modify Onion Markers pop-up (the rightmost Onion Skin buttonpictured in Figure 7.7).
Figure 7.7 The Modify Onion Markers pop-up has several preset options.
Modify Onion Markers has several preset options:
Always Show Markers leaves a faint version of the markers visible in the Timeline even after you turn off Onion Skin.
Anchor Onion locks the two markers where they are (no matter where your red current frame marker is).
Onion 2 sets the markers to two frames ahead and two frames behind.
Onion 5 sets the markers to five frames ahead and five frames behind.
Onion All moves the Start Onion Skin Marker to frame 1 and the End Onion Skin Marker to your last frame.
Before we finish with Onion Skin, let's look at two remaining features: Onion Skin Outlines and the Edit Multiple Frames option. You can choose either Onion Skin or Onion Skin Outlines, but not both. Onion Skin Outlines displays the other frames within the Onion markers as outlines instead of as dim images. Outlines can be helpful if you have a particularly slow computer or if the dim view makes images difficult to distinguish.
Finally, Edit Multiple Frames is quite interesting. In the previous task, we used onion skinning to see the contents of surrounding keyframes, but we were editing only one frame at a timethe current frame. We could move the stick man's leg close to the faded image in the previous frame without affecting the previous frame. Edit Multiple Frames lets you edit the contents of all the frames within the Start Onion Skin and End Onion Skin markers. Generally, Edit Multiple Frames is useful for editing a finished animation rather than creating an animation because you would never know which you're editing. However, when you want to return to an animation and move the contents of every frame, Edit Multiple Frames is invaluable. In this situation, just turn on Edit Multiple Frames, select Onion All from the Modify Onion Markers menu, select everything onstage (press Ctrl+A), and move it anywhere you want.