Particle over time, not life?

naked_chicken

Is there a way to affect particles over time rather than over life? Like no matter what the lifetime is of a given particle it's velocity will be affected the same after 3 seconds.

EmAr

I'd try modifying particle parameters in Kismet. You can choose what variables you want to edit in Kismet by choosing particle parameter type distributions for them in Cascade.

imbueFX

There are lots of different tricks and hacks depending on what it is you're trying to achieve. Some modules actually have a "use emitter time" like the orbit module or dynamic parameter module.

For something like velocity, I personally would animate an acceleration module as a simple and easy starting point. Can you be more specific on what you're trying to achieve? I may be able to give more direct advice that way.

EmAr is also right in making it a parameter, at that point an outside source can control any value directly over time. This gets more complicated and requires setup outside of cascade, which is why I only use it when necessary.

imbueFX

And I'm realizing I didn't directly answer your question: No, not everything has a direct way of being animated in emitter time versus particle time. An example would be animating the initial velocity module, let say you animate so that at 2 seconds in, velocity on Z is turned on. That Z velocity will only occur on particles spawned after 2 seconds.

naked_chicken

So say you've got a stream of particles coming out and they have infinite life, they only die when they collide with something (not optimal I know but it's an example). But I want those particles to start arching downward (as if by gravity) over time. You can't use over life because they have infinite life so none of those modules work.

Any ideas?

imbueFX

I'd just animate acceleration in that case. I think it'd work perfectly and should work independently from lifetime. Don't use accel/life, that'll go back to your original problem.

naked_chicken

Sorry I wasn't very clear, I mean I want them to arch down. If I animate the velocity then they will just angle down from the emitter. I want them to keep going straight out for a second then start arching down.

imbueFX

Right I got you, re-read my previous post. Acceleration is different than velocity, it's a cumulative force. Kind of the opposite of friction, if you will.

naked_chicken

That does a pretty good job actually but I ran into another issue. Is there a way to animate acceleration besides the "over life" node? Say I wanted to reverse acceleration when you hit a trigger. I can't seem to find a vector particle param option in matinee. The vector param just gives me draw 3d scale. Does nothing for me sadly.

naked_chicken

Nevermind, I was trying to do it with matinee, kismet has what I need.

imbueFX

You still can do it with matinee as well (I find it to be easier than Kismet IMO).

Just right-click on the group in Matinee and select "Add New Float Particle Param Track".

Glad you got it working the way you wanted!

naked_chicken

Tried that but acceleration is a vector particle param and the matinee float particle param didn't seem to work on it.

imbueFX

You are correct, I thought of that as soon as I posted my last piece of advice

It's a pain in the ass, I'm not sure why they don't have a vector parameter for particles.