Trailing particles

Hi,

Is it possible to make particles which trail behind when the emitter moves, rather than having all the particles follow the movement of the emitter as a whole? That is, whatever absolute path the particle is following when emitted should not change when the emitter moves. Think of like the smoke from a skywriter or writing letters with sparklers. I can’t seem to find a way to make this happen.

T

Turn down the Velocity (velocity controls the speed of the particle) and turn up the Life to make them last longer.

%<

Hi, thanks for the reply. I’ve tried with several of the options under velocity, but I haven’t had any luck getting the particles to trail the emitter. Life is at 5oo and the partilcles seem to be hangng around long enough, but they are still moving along with the emitter when the emitter moves.

T

I’ve tried with several of the options under velocity

You should only use Normal, at probably 0.010 or less. Turn all others to 0.00, except Damp, you can have high Damp value so the further the particle gets from the mesh the more it is dampened.

%<

It’s not working for me. I’ve got normal at .005, damp at .5 all other velocity values at 0, and life at 500. What I get is a very small, dense ball of smoke that sticks to the emitter wherever the emitter goes. Not even a hint of anything trailing behind.

I think that one way or another, I’ve got things in a state where the velocity, etc, is all calculated relative to the emitter, rather than relative to the world. Is there some kind of switch for this?

I wonder if animating the object internally (i.e. with RVK or something like that) might be the answer.

Well I just tried doing it the standard way, and it worked. I can’t think what you must have done for it not to work. Presumably they’re non-static particles?

Yeah, they’re non static. They move fine in relation to the emitter, they just follow it everywhere, like children objects follow a parent object. The truth is that this is an object which I downloaded and adapted, so there may be some non-default settings I’m not aware of. I’ve tried tweaking things that might be related, but I can’t seem to change this behavior. I’ll try making an object from scratch and seeing if it acts differently.

Oh. Well… that worked. Doh!

Thanks, guys.

Ah, not so fast. The problem is when the emitter is following a vertex parent. When I do this, the smoke no longer trails. I’ve tried both single vertex parenting and 3-vertex parenting.

The motion is pretty simple and brief, so I could simply key the movement of the emitter independently of the object, and not use a vertex parent. But it’d be much nicer to get the trailing effect with a vertex parent. I can imagine a lot of cases where this would be handy.

It’s weird that the particle system should behave so differently when keyed as when following a vertex parent. Is this as designed?

What does it do with a CopyLocation Constraint?

%<

I was wondering that too, but so far I haven’t been able to get copy location to work properly here. When I try to copy location from a vertex, the object jumps to a strange place. I tried vertex parenting an empty and then copying the location of the empty to the emitter, but when the empty moved (following the vertex parent), the emitter didn’t move. Furthermore when I looked at the empty’s location with the N Key it didn’t seem to change values, even though the empty was visibly moved. I’m using ctrl-c to do the copy location. I’m not sure if that is an actual copy location constraint or not.

No, you need a real Constraint from the Constraints tab. I tested it and it works.

%<