your talking about the ipod-like streak tutorial that uses particular, right…?
since the particles are very tightly space (actually, more like overlapped) to create the streak, i think you would want to create a new particle system for the letters with a lower birth rate, so you could actually see individual letters.
you should be able to choose the same emitter as the light streak, so the letters will seem to be coming from the same source as the light streak. if not, create an expression to link the second emitter’s position to the first emitter (just enable expressions for the new emitter’s position, then use the expression pickwhip and point it to the original emitter’s position parameter).
to create the letter particles, you will need to create a new comp approximately the size of the letters and the length in frames that is equal to the number of letters (and spaces if needed). then create a text layer and type the letters as you need them to appear. now add this expression to the ‘source’ parameter of the text layer:
letterArray = value;
letterArray[time/thisComp.frameDuration]
this will display one letter per frame of the comp.
bring that letter comp into the particle system comp and choose it as the particle layer, set the sampling to split clip – loop (or if you wanted random letters, choose ‘random – still’) and set he number of clips to the number of frames. this will emit each letter as a static particle.
adjust the particles/sec to keep the letters legible.
Kevin Camp
Designer – KCPQ, KMYQ & KRCW