I have a tutorial on my particleIllusion DVD that *sort of* covers some of this, but not quite. Let me see what I can do...
OK. This assumes that your stroke effect is animated with 2 keyframes, and doesn't change speed. If you have more than 2 keyframes, and that causes it to change speed, this will not work.
- Select the layer with the stroke effect.
- Hit M to reveal the mask path.
- Select the word Mask Path.
- Choose Edit > Copy
- Create a new Solid layer the same size as the stroked layer (I assume it's the same size as the comp).
- Select the new solid, and hit P to reveal the position property.
- Select the word position and choose Edit > Paste
This create position values that create a motion path that matches the Stroked mask shape. The position keyframes are created as roving keyframes. If you don't know about that, watch my tutorial here at the cow covering that.
- Next, on the new solid, drag the last position keyframe to line it up with the Stroke effects last End keyframe.
If you check you will see that they are animating together. The new solid's anchor (center) point should be a perfect match for the front of the stroke as it's drawn on.
- Next, Alt(option)-Click on the new solid's position property stop watch - this adds an expression.
- Hit Enter on the number pad to confirm the expression.
Even though the expression changes nothing, it's still there and we need it for the next step.
- Next select the position property for the new solid (which selects all keyframes) and choose Animation > Keyframe Assistant > Convert Expression to Keyframes.
This creates a keyframe at every frame. We need this so that particleIllusion will get every single frame of animation from AE. Otherwise it would only get part of the data and the motion would not match.
- Select the word position (which selects all position keyframes) and choose Edit > Copy.
- Then go into pIllusion, and paste keyframes as you normally would.
That should do it.
You may find that you need to offset the video when you bring it into AE. I have a feeling that you may want to have the video start playing about 1-3 frames before the stroke starts animating. Particles take time to appear, and the stroke may appear before the welding sparks. But if you have the stroke start animating 1-3 frames after the particleIllusion footage, that should fix it. I might be wrong, and you may not need to do this.
Aharon Rabinowitz
Email: arabinowitz (AT) yahoo (DOT) com
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Internet Killed the Video Star: A Guide to Creating Video for the Web
