I'd like to position the emitter in particular 2 to one point on animated 3D enabled image layer. If I parent the particular layer to the image, I'd need to turn on 3d for the particular layer, or it doesnt seem to stick on, if I do turn on 3D, particular says I should only be using 2d layer, how do I achieve this? Thanks in advance.
Particular works in AE space by projecting particle from a 2d layer into AE's 3d space. If you turn on the 3d for the layer, ignore the warning, twirl down rotation and rotate on the y axis, you'll see clearly that particular is a 2d effect. In essence it has it's own 3d space that works within AE's 3d space. Hope that makes sense, cause it's an important concept in working with particular(or any of the Faux 3d effects in AE).
There are a couple of methods you can use to tie the emitter to a position in 3d, one would be to write/pick whip some simple expressions to the emitter position.
A easier solution is to use a 3d light as your emitter. Create a light and rename it "Emitter"-has to have that name(you can change the name, if you open up the options of particular). Open up particular and change the Emitter type to light and now you can move that light/parent it to a 3d object and your particles will be generated from it.
You may want to look at the Particles/sec modifier. By default it uses light intensity to modify the amount of particles-so you might want to change that to "none".
Johnny Cuevas, Editor
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.