reversing particle system?

I want to get an object to absorb particles (like a vacuum cleaner). It should pretty much look like a simple particle system when played backwards. I tried with the time IPO the way it is described here:

It says “The Time curve is especially interesting for particle systems, allowing you to “freeze” the particles or to animate particles absorbed by an object instead of emitted.”

Well, in my case this does not work. I can freeze the particles by putting the time IPO horizontally. But as soon as the time IPO goes down (from top left to bottom right) the particles disappear.

Any suggestions?

I see what you mean, I just tried it as well. Particles just stop or go away when they travel backward in time.

Your best bet is to render out the image sequence with an alpha, then play it backwards.

Thanks, Atom.
Yes, but in my case this solution won’t do it. It is only a part of a bigger scenery with three different particle systems. The vacuum-cleaner effect on the left of the picture, the particles-through-hose-effect in the middle and a particle-spread-out-in-tank-and bounce-around-effect on the right. I need to move the camera freely within this scenery to implement my client’s corrections quickly without rearranging the entire scenery.

I did a vacuum-cleaner-effect for the same client some years ago with blender. I just checked out my old file and found out that I did it successfully with the IPO-reverse-idea. In older versions the IPO-reverse seems to work on particles (but the curve-guides and collisions don’t). Newer versions do a great job on collisions and curve-guided particles whereas the IPO-reverse feature has gone since the particle system has been rewritten. This really brings me into trouble. I’m pissed…:mad:

It probably worked before the Jahka particle system was installed as the official system. I think that might have been 2.42 or earlier. Either way it looks like you might be faced with using a rendered image sequence, going back to an old version of Blender or simply using other software that has a more robust particle system. Like C4D, 3DSMax, Maya etc…

Blender isn’t the only tool out there.

Thanks so far, Atom.
Yes, I will try to render this part of the scene and play it backwards. It is complicated, though - because it is mixed with lots of different animation, physics and stuff (this is why it won’t work in older versions)

Meanwhile a new problem occurred: Particles do not really stay within a collision object (hose). Every now and then one of them escapes. The more faces, the more particles break through the wall. Only primitive cubes really keep all of them inside. But I post this with a blend file in a new thread.


It involves baking the particles to disk and then renaming the baked files, a little hacky but its usable. I’ve written a very basic tutorial here

hope it helps!