Particle spurts

[JCook]

I'm having a little problem with particles. I'm using ASPro 6 on a Mac.

I've got a particle layer that starts at a certain time. The particles begin, and flow, and then there's a gap and the start again, then a gap, and so on. I can't find anything in the particle settings that affects this. I'm using a particle that is following a path, as in the water tutorial that LM posted some time ago. I've done this numerous times and haven't had this gap problem. What I want is continuous flow once the particles start. Any ideas about this?

thanks,
Jack

[JCook]

OK, I haven't solved the problem yet, but I've noticed that it seems to happen with any particle group that I don't have turned on at the beginning of the animation. I've got several particle groups in my animation, and some of them are just continuous from beginning to end. Those groups seem to work fine.

But I've got a couple of particle groups that I don't want turned on until a certain time, and with those I get this spurting effect, where the particle emitter emits a bunch of particles, then no particles for a frame or two, then another bunch, etc. Seems to be consistent with turning the particles on at a frame other than 0. Is this maybe a bug? Is anyone else having this problem?

thanks,
Jack

[Barry Baker]

I had this happening to me as well, on v5.6. I thought maybe it was running out of particles, because they were all flying around the screen, so I tried upping the particle count, but I still had the same thing happening.

In the end, I used a workaround, which was to duplicate the particle layer, and set it to start spurting every time the other one gave up. That way it gave the impression of a continuous stream of particles.

I haven't tried on v6 yet.

[JCook]

Hi Barry,

Your workaround may be the way I'll have to go. The gap is only a few frames, maybe a quarter to half a second, certainly no more than one second, but it's very noticeable. If I put in duplicate particle layers, I guess I might have to decrease the amount of particles in both layers so as to not have too many. I'll play with it.

thanks,
Jack

[JCook]

OK, here's an update.

I've been mucking around with this, and I think it's linked to the "On at start" checkbox in the Particle Layer dialog box. When this is checked, it seems that the particles work alright and flow smoothly, pretty much. But when you start the particles at a certain frame (any frame) then you get the spurting behavior. Also, the particles start off slowly, and come out with the first bunch all piled on top of each other. My particles are mostly letters indicating chemical elements, so this is really noticeable. When you have the On at start box checked, and the Full speed start box checked the particles are fine. I am also using the Even spacing option. But the Full speed start option isn't available if you don't check the On at start box, which may be part of the problem. I don't know why it would cause the spurting behavior and gaps in the particles - I would think the particles would just have to accelerate to speed and then it would be ok, but there are definitely gaps and groups of particles being emitted.

So my workaround is to have the particles on at start, and then use the Visibility option in the layer to make them suddenly appear when I want them. It works, but it's not the effect I'm looking for, but it'll do.

Jack

[slowtiger]

You might want to render one scene with the particles starting right at frame 1 (and be visible), and a second scene without particles which you edit in front of the first in post pro.

[Barry Baker]

Or, you could use a soft-edged mask layer to reveal the particles more gradually, spreading out from the source over a few frames. That would more accurately mimic the effect of the particles starting up on a particular frame.

[JCook]

Excellent idea, Barry. That would give the effect of the particles starting from one point and going to the next instead of just appearing fully blown. I think I'll give that a try.

Jack