There’s more than one way to do it, but something like this should work:

 

minSpeed = 0;

maxSpeed = 500;

minParticles = 10;

maxParticles = 1000;

N = thisComp.layer("Null 1");

linear(N.transform.position.speed,minSpeed,maxSpeed,minParticles,maxParticles)

 

 

Dan

 

From: Chris Biggs

Sent: Thursday, January 05, 2012 6:51 PM

To: After Effects Mail List

Subject: [AE] Attention Expression Gurus

 

I'm working on a project that requires a Base comp be built that all the artists can use.

it's a Trapcode particular effect that needs to add to amount for particles emitted depending apon

velocity of the emitter ( using a null to drive the emitter)

i.e. moving slower less particles, faster more particles.

 

any suggestions ?

 

Thanks

Chris

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R.Christopher Biggs
Digital Ronin