Hi Alan,
Thanks for the kind words and for the “spray” advice!
I used the Star Trail 2.0 emitter. Typically I animated the entire emitter’s zoom property to account for camera zooms. On some shots I had to adjust the size of the big glow particle to keep it reasonably sized wrt to the rest of the emitter.
I tried tracking the balls in AE, but the ball moved behind obstructions too often for me to get a good enough track.
That left me with performing roto in pI, which I did. I exported each background clip from AE as a 648×480 HuffYUV .avi file so that pI would accept it as a background. The emitter stage was also sized to 648×480
With very few exceptions, each position keyframe in pI was created “curved”. That allowed me to adjust the bezier handles to account for changes in both ball position and ball acceleration over several frames without having to add a keyframe for each frame. Not having a keyframe for every frame also smoothed out the motion of the particles quite a bit.
Once I had the emitter’s path complete for a given clip, I imported the emitter into AE as a 32-bit .png sequence. Then I dropped it into a 720×480 (0.9 PAR) comp and started masking. That involved more roto work because I needed the emitter trails to be behind some players and in front of others. So I animated the masks field-by-field in 59.94 fps comp to make sure that the emitter trails appeared to be behind the players when appropriate.
If you’d like any examples of my pI or AE projects, I’d be happy to email them to you (sans footage, of course).
Best,
-Jeff
The Focal Easy Guide to Adobe Encore DVD 2.0