Muting particle emissions...

[Matthias Worch]

...but still having the particles on screen finish their journey. Kinda tricky, I found out.

I'm trying to create an energy rifle mockup for a game, so I made a simple particle system that continuously emits particles into the world. The particle system is attached to a guy running around in the world. The idea is that I'd mute the emission of that particle system by default - but when I want the character to "shoot" I key the Mute property to be inactive - the particle system emits particles (the guy is "shooting") until I mute the emission again.

That works with one little snag: as soon as I mute the emission, it doesn't just stop firing new particles. The particles already emitted disappear as well! :(
Does anybody have a solution for that? I want to fire particles when emission is active, and I want those particles to stay around when the emission is muted. I just want the particle system to stop firing new particles as soon as emission is muted.

[Thiago Costa]

Animate the "Rate" instead of mute the entire particle emitter.

[Steven Caron]

key the rate of the particles down to zero

steven

[Matthias Worch]

Uh...doh? :)
That'll work, but I'll have to account for the step tangent so that the rampup is not gradual, I guess.

[Eric Lampi]

You can see how it worked out here:

www.psyop.tv/ubisoft

E

 

Freelance 3-D Animator, F/X Artist

[Eric Lampi]

I did something a while back where I keyed a cyclical animation on the emitter's rate, 20,000 for a frame or two. 0 for a frame or two - constant curves in the f-curve editor, the result looked like a machine gun firing.  Saved it as a mixer clip and linked the mixer to a square which allowed the animators to control the machine gun firing without having to mess with the simulation at all.  It's either firing or it's not, and when it's firing the rate was already cycling.  They set up their keys, cache it and it was good to go.

[Matthias Worch]

Cool, thanks. Dunno if I'll go to those lengths because nobody but me will ever work on this, but it's a neat solution.