Particle point/Spawn Trail uniformity

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Joined: 10 Jul 2009, 20:52

Particle point/Spawn Trail uniformity

Post by Roughy » 10 Jul 2009, 21:18

I've been trying to set up a fairly simple trail of particles emitting from the points of my primary cloud. For the most part it works fine, but, regardless of whether I use the Spawn Trail node or set use emit_from_position with the points of the primary cloud plugged in, I end up with uniform emissions.

Basically, although the particles move about independently afterward, they emit on the same frames; there is no variation in when they are emitted between positions/particles

With the age limit set to 2 frames, we get this:

Same thing for both the Spawn Trail compound and a completely separate cloud with only the spawn positions pulled from the primary cloud.
I don't really see why they end up being uniform to begin with, so I most certainly have no idea how one would randomize them.

Any help would be appreciated

Posts: 70
Joined: 18 Jun 2009, 19:58

Re: Particle point/Spawn Trail uniformity

Post by Matic » 11 Jul 2009, 22:10

When using the 'spawn trail' compound, low rates will cause a stuttering effect like I see in your image sequence. Do you want a single particle emitted each frame? I'm unsure what you mean by uniform emission...

I am guessing that what you want is something like this... for every frame, there is a (defineable) chance each of your original particles will spawn a new particle. Here's a simple example using states to do this kind of thing. I am comparing the time in state to a random value, and if the time is greater than the random value (which is slightly different each frame) the second state is triggered, which causes a particle to be spawned. The second state immediately reverts back to the original state (the trigger is set to "true) which in effect just resets the time in state on the original particle without changing anything else.

Here's a screenshot ...
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