So, I'm very new to After Effects (just started CC free trial a few days ago) and I'd like to think I've got the hang of it fairly quickly with tutorials and experimentation, but I'm running into an annoying problem in one of my test projects. I have a Particle World attached to a null object, and the animation for emitter position, gravity, etc will not update! I've looked around for a couple hours trying to find a solution to no avail...
It's simple footage of me waving my hand around and I want magic dust to follow it and then start falling quickly at a certain point, so I have the emitter's position linked to a null object that follows the path of my hand, and the transform position linked to another null object that tracks camera movement (so the trail moves with the rest of the purposefully shaky footage), and the gravity animated such that it stays at 0 until I want it to fall. This works fine when I first create an animation, but if I want to change anything it won't update in the preview window despite the numbers giving me correct information -- and the weird thing is that if I adjust the position path of the null object following my hand it'll work with the first few keyframes but not beyond those; that is, the path will update (including the lens flare object that's also parented to it) but not the particles. I've tried reloading the project and I've heard that clearing the cache works but I'd rather not do that every time I update something... If I disable animation and change the value it works fine but as soon as I re-enable it it goes right back to how it was.
If it helps anything, I'm mostly following this tutorial: https://www.youtube.com/watch?v=81oz2rtAtYk for the effect.
Sorry for the newbie yet seemingly complicated problem... Any suggestions?
[EDIT] So, I figured out why the gravity wasn't animating: changed gravity doesn't affect pre-existing particles. Should be easy enough to fix I guess. However, there's still the question of the path only working partway through...
It's virtually impossible to tell without getting a look at your full timeline, effects, keyframes etc - but one thing that comes to mind is: could you have possibly set a 'hold' keyframe/s? This keeps it's value until the next keyframe, rather than iterpolating between keyframes, and could give the impression things are not updating.
See 'keyframe interpolation methods' a little way down this page: Keyframe interpolation in After Effects
Hit U on the keyboard with no layers selected to reveal all your keyframes.
Thanks for the link, I'll take a look at that and see if I notice anything. Now that I've had time to think and learn a bit more, I probably messed up some obscure thing in the creation of it because I was experimenting with everything else. Thanks again!