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### Particular: Gravity over time?

Posted: 01/27/2017, 3:02 pm
Is there a way to animate the Gravity of the particles over life where gravity is low, so the particles rise up, but then the gravity rises as they reach the end of their life? Keyframing Gravity itself, or using "Physics over time" effects all particles, whether just emitted or at the end of their life span.
If you think of it like a ceiling. Everything rising like smoke, but then the smoke/particles (no, Im not making smoke, but was the closest analogy I can think of) reach the ceiling and accumulate there.

I was phrasing the question wrong, or maybe better yet, approaching it all wrong. I Searched "after effects particular control speed of particles over life"
It came back with https://www.reddit.com/r/AfterEffects/c ... _question/
You play with the air and velocity instead of gravity Hope this helps someone else.
The only problem this still doesn't solve is if you're needing to emit a constant stream of particles that go up, and then down like on a water fountain or something.

### Re: Particular: Gravity over time?

Posted: 01/27/2017, 6:21 pm
try using the following expression in gravity.

time*'number' replace number with an actual number and the effect will be compounded over time.

### Re: Particular: Gravity over time?

Posted: 01/28/2017, 9:53 am
First off, thank you for your time and response.
Let me try this, and Ill let you know. I feel like this will impact the layer as a whole, and not effect the characteristics of the independent particles over their lifespan.

### Re: Particular: Gravity over time?

Posted: 01/28/2017, 1:13 pm
I got a chance to try out your expression and Im confused. So, initially it was just an assumption that keyframing "Gravity" under the physics tab would effect the particals as a whole, as a layer. But when I went to try out your expression, it occured to me that "Gravity" doesn't allow for key framing. or am I missing something?

### Re: Particular: Gravity over time?

Posted: 01/28/2017, 5:46 pm
I kinda had that thought in my head but I wasn't sure, sorry!

Maybe some sort of aux or bounce I dont know. You may have to resort to a 3d particle system in a dedicated program. Good luck

### Re: Particular: Gravity over time?

Posted: 02/2/2017, 9:39 am
Still haven't any fix to the the gravity issue, but I had a thought. Is there a was to control the speed/time of a section of a layer with a mask and some sort of gradient ramp?
Also, Im rendering what I have so far. Definitely not done, but its close. One problem I can't seem to get right though is how to make the form layer not so symmetrical with its dots. They are in straight lines. Is there a way to scatter them a bit. I've messed around with every parameter/setting, and nothing.