tirigger emitter with marker

[Sarah Schela]

I think it could be done with a simple if-else clause.
is there is a marker, emit 1 particle, if not, stay zero.

but I seem not to be able to accomplish this simple expression….

please, help!

[Xavier Gomez]

You can try this (expression to put in the emitter’s emit rate property, change “Null 1” to the name of the layer carrying the markers):

// the emitter emits at the control layer's markers
// the emit rate at markers is controlled by the emitter key value
// how fast it decays after each marker is controlled by this param:
decay = 25;

// get last key index;
m = thisComp.layer("Null 1").marker;
idx = m.numKeys ? m.nearestKey(time).index : 0;
if (idx && m.key(idx).time>time) idx--;
//
(idx<1) ? 0 : value*Math.exp(-decay*(time-m.key(idx).time));
Xavier

[Sarah Schela]

oh wow, it seems to work in the right direction!
That’s fantastic! Thank you a thousand times!!!

Only thing is that my beat is quite fast. and I need to adjust the number per second to a higher rate, like 10 or 20, not 1 per second.
Do you know where I can adjust the value?

[Xavier Gomez]

Hi again,

it’s not completely clear to me what number you are refering to.

If it is how many particles are emitted at each marker, do it by changing the emit rate value (which the expression reads for its final output).
If it is to emit not at all markers but say every 3 markers, something like this, or the other way round, 3 times between 2 consecutive markers, then the expression should be modified slightly.

Xavier.

[Sarah Schela]

Hello Xavier,

oh, I see! That fixed my problem! I meant the particles emitted at each marker.

Again, thank you SO SO much. you saved my life, otherwise I would have spent my night setting keyframes…