Particle Playground rain

[Tristan Nieto]

That sounds like a seriously complicated effect. Particles that subdivide and mapping them over complex shapes like moving actors sounds like a job for 3D, or possibly trapcode.

However, in Particle Playground you can use the Persistent Property Mapper to affect particles using another image as a map. You could probably generate a map by rotoscoping your actors, (unless they’re on a greenscreen or something), then using a combination of coloured ramps and maybe a bit of motion tracking to give you vaguely human blobs. That may give you something approximating a displacement matte that you can use as a map to offset the particles’ positions (and possibly even the scale, not sure), but it would be an awful lot of work to get an effect that might not work like you want it to. And you still wouldn’t get your raindrops to split into little ones.

Of course, there’s always hand animating every raindrop.

Not sure if it’s on here or another site, but look for a tutorial about using Particle Playground to generate snow particles that stick to things. Might be a good start.

Hope this helps.

Tristan

[Kevin Camp]

yeah, i think unless your subjects are already keyed, or static enough to make a quickie roto-mask to use as a layer map in particle playground you may want to modify what you’re going to accomplish with particle playground…

but if you can generate a grayscale matte layer easily enough to use as a layer map for various properties in particle playground then here are a few things you might try get close to what you want…

your map layer will need to be for the most part a white subject on black background, once created, bring that into the same comp as the particle playground effect and hide it.

set the ‘particle exploder’ to use the subject matte as the selection map and you’ll need to do some tinkering with the radius of the new particles to get the number of smaller drops from each big drop the way you want it. the smaller drops will use the same rain particle defined as the layer map if the affects particles from property was set to ‘all’. don’t worry about the actual scale of the smaller drops for now, that will have to be handled with another property, your jsut interested in how many drops will be created with each particle explosion.

you’ll probably want to use the same subject matte as a repeller layer in the repel settings… for now just set the force to 1, you can tweak it later.

to get the smaller drops to actually be smaller, create a new white comp sized solid and hide it. inthe persistent property mapper set the white solid as the layer map, set affects particles from to ‘particle exploder’ and map ‘red’ to ‘scale’ and set the max scale to the same value as needed (like .5 or .25…). this will make all the particle exploder drops smaller than the main drops.

you may also want the smaller drops to rotate, you can set that by using setting the persistent property ‘green’ to angular velocity. try a max value of 180-360, tweak as needed.

you’ll have to see if this gets you close to what you are after…..

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW