Tutorials

Prepare Illustrator artwork for animation in Flash

by Sharon Steuer

Seattle artist and animator Kevan Atteberry knows how to get the most from Illustrator when preparing artwork for animation in Macromedia Flash. Besides making his Illustrator file a sketchpad filled with the eyes, ears, arms, and legs of the character he will animate later in Flash, Atteberry uses the Layers palette to preview parts of the animation. He also exports a Flash animation from Illustrator to view as a draft version as he works on the final animation in Flash.

1. Sketching characters, drawing body parts.
Atteberry began with a custom calligraphic brush, sketching a series of facial expressions and figure poses, honing the visual character of a lemur until he was satisfied with the characterization and ready to construct the lemur's body parts.

Figure 1: Character parts sketched with a custom calligraphic brush

Once you're done drawing your character's parts, you can keep your artwork as Illustrator objects or turn the artwork into symbol instances.

Figure 2: Symbols palette displayed in large list view

It takes fewer steps to convert your artwork to symbol instances in Illustrator than to bring your artwork into Flash and make symbols there. Also, if you plan to export a Flash movie from Illustrator, turning your character parts into symbol instances results in a smaller and faster-loading Flash file. To make symbol instances, select the artwork for each part body you drew and Shift-drag it into the Symbols palette. After you release the mouse button, Illustrator adds the artwork as a symbol in the Symbols palette and replaces the selected artwork with an instance of the symbol that was just made.

2. Making brushes, creating blends for objects, expanding blends, and creating symbols.
For any part you animate, you will need to create a sequence of parts for example, a leg that moves from straight to bent. Atteberry created art brushes for the lemur's moving parts, so he could paint each part in the motion sequence with the brush.

Figure 3: Two of the brushes Atteberry created for the moving parts

(This saved the effort of creating separate art for each part in the sequence.) First, draw a straight version of the part. When you have the look you want, drag-and-drop it on the open Brushes palette. In the New Brush dialog box, choose New Art Brush.

Next, you'll create artwork for the two extremes in the motion sequence. Draw the straight part, and a few inches away draw the bent part. Select both paths and apply the art brush to both.

Figure 4: The straight and bent lemur legs representing the extremes of a motion sequence that Atteberry used to create a Blend

Now, to make other parts in the movement sequence, make sure both paths are selected and choose Object >Blend >Make; then choose Object > Blend >Blend Options and key in the number of steps in the Spacing: Specified Steps field. Consider using a small number of blend steps Atteberry uses three or four so that if used as frames in a Flash animation, your SWF file will have a smaller number of frames and a smaller file size. Finally, expand the blend (Object >Blend >Expand) and ungroup it so you have separate objects to use in constructing poses for the motion sequence.

Figure 5: A blend using three steps created between the straight and bent lemur legs

3. Exporting an SWF animation.
Once your artwork is complete, you can export the file as a draft or final animation that you can view in a browser or in the Flash player. To prepare your file for animation, first add as many layers as frames needed to show the motion sequence. Treating each layer as an animation frame, assemble the artwork for a particular pose or step in the motion sequence on each layer. Move from layer to layer, creating renditions of the character on each layer until the character has performed all of the poses or movements you want to preview. When you have completed all the layers, select File >Save for Web. From the Format pop-up, select SWF (just below the word Preset) and, from the pop-up below that, choose AI Layers to SWF Frames. If your animation will use a lot of frames, or will include complex motion sequences that require many intermediate poses or steps, create the final animation in Flash instead of in Illustrator. Flash's tweening commands automatically create many of the intermediate poses you would otherwise assemble manually in Illustrator.

There is another animation technique you can use to preview motion from within Illustrator itself. Atteberry constructed a draft version of part of the animation to preview the look of objects and of the motion sequence. To do this, you can construct a preview by first following the steps described above for positioning poses on successive layers. After you've filled all your layers with artwork, select Palette Options from the Layers palette menu. Click on the Show Layers Only checkbox to enable this option and key in 100 pixels in the Other field. To preview the animation, position the cursor over a Layers palette scrolling arrow and press the mouse button to cause the layer thumbnails to scroll like frames in a projector.

Figure 6: Previewing a motion sequence using Illustrator's layers palette as a crude film projector

Exporting an SWF file to import into Macromedia Flash.
To create complex animations, instead of Save for Web, choose File >Export and choose Macromedia(SWF) from the format pop-up. After naming your file and choosing the file destination, use the Format Options dialog box to choose options for creating SWF animations. One choice available only from Export is AI Layers to SWF file; this can be a very useful option for continuing to work on your artwork in Macromedia Flash.

To assist in constructing his animation "Millard and the Pear," which is described in the previous lesson, artist Kevan Atteberry developed a file of recyclable parts a cartoon "morgue" from which he copied parts and pasted them in the file in which he created the animation.

To trim the file size of the animation, Atteberry converted the artwork for parts into symbol instances by Shift-dragging them to the Symbols palette. When he needed to edit a symbol, Atteberry selected the instance and chose Object > Expand.

After editing the artwork, Atteberry selected the artwork and Shift-dragged it to the Symbols palette to automatically convert it back into a symbol instance.