I seem to be fighting with motion, rather than working with it.
I cant seem to get the following end result:
Particles spawn from a particular spot, which is tracked.
Particles are drawn to another location, also tracked, with a gentle curving motion away from the direct line.
What Ive tried:
1. Motion path. Cant Seem to get the particles to follow a path at all. I can get the emitter to follow a path, but that isnt quite what I want and has its own problems (it wont follow a path that has control points that are tracked).
2. Attractor + Repellor. Tons of odd behaviour here. System seems to stomp on one or the other.
3. Attractor + Wind / Gravity. Almost can get it, but only after an overshoot. Different code path for overshoot vs heading-towards?
I'm not exactly sure the effect you're trying to achieve but for one thing particles don't follow motion paths at all, but you could cheat something like this. I.e., particles are different beasts than normal objects.
One way to create a "particle stream" effect would be to make your particle emitter's Emission Range be 0 degrees and really crank up the Life and Speed parameter values and then control it with null objects with the Attractor, etc. behaviors applied to them. It is a bit tricky since the "end" particles seem to be the ones that are attracted to the nulls, but maybe with some tweaking.... :)
[Marc Hernandez]"I tried making an emitter of emitters, but was denied."
Actually you can do this, at least with most of them. The trick of course is to make an emitter out of the emitter's Group, not the emitter itself. Likewise you can Replicate a Replicator or a Particle Emitter using this method. (Just don't use the Replicator on a Replicant; we don't want 500 Roy Battys running around!)
Actually I think the type of functionality you're looking for may be possible in future versions of the software.
A (partial) Motion 4 wishlist:
2)Particle motion path/"pipes"/"waterfalls"/"channels"/"funnels" (or whaever cogent paradigm you prefer)
3)Something similar to AE's "pick-whip" expression linker, but a much more elegant implementation