Expressions plus manual input should do the trick – best to check out the COW’s AE Expressions forum where the Expresso Experts hangout. I’ve actually done an effect where a dot controls when text characters appear. Essentially, a text animator’s opacity is controlled by the x-position of the dot.
As the dot moves, its x-position is passed on the the Text Selection parameters. If you can do this, then simply link the dot’s position to the particle emitter.
The only issue I had was that a text string has different left and right edges that are dependent on the actual characters. I have to manually input offset values that require a bit of tweaking before getting things right. Again, the Expresso folks may be able to automate this offsetting process
I’ve go the AEP on the other machine which is going to be tied up for quite ahile and unfortunately, I don’t have the confidence to type out the script now without beng able to test it out.
So, yeah, give a yell out to the Expresso folks around the corner.
Cheers
RoRK
broadcastGEMs.com – the leader in customizable royalty-free animated backdrops