How can particles be used in local space?

[Deltakosh]

Yes which is expected based on what I mentioned earlier. What would you expect differently?

[Wingnut]

I guess… nothing. I have never used GPU particles. I don’t know what to expect.

So… taking 2+ minutes to arrive at 1000 emitRate… is normal? If so, I’m cool. Sorry for the goose chase… I have much to learn about GPU particles.

I wonder if it could take over 4 minutes… to “plateau” (level-off) at 1000 emitRate.

I wonder why GPU particles are so much more “intense” after 2 minutes… than CPU particles with same settings.

I wonder how we can tell… WHEN it DOES plateau. (I wonder lots of things.)

This GPU stuff is too powerful for Wingy, me thinks.

[TheStupid]

Hi,
Thank you @Wingnut and @Deltakosh for your help, especially for the playground by Wingnut.
I will mark your approach as the solution. It is not perfect but with the tools available it seems to me (who is not that experienced) the best possible.
Maybe the developers will use this thread as inspiration for their next big update.
Have a nice day.

[Deltakosh]

@Wingnut

taking 2+ minutes to arrive at 1000 emitRate… is normal

The emitRate is at 1000 since the beginning. 2 minutes is the time to reach 1 000 000 particles.

I will immediately update the doc to clarify that

[Wingnut]

I still don’t understand. Sorry. Visually, it appears that the emitrate increases to approx 5000… after 2 minutes. Are you saying that emitRate is a PERCENTAGE of total particles in the pool?

Here’s an example: https://playground.babylonjs.com/#PU4WYI#107

Programmer wants users to ALWAYS see the yellow box behind the particle stream. Progger starts scene… all looks good… until 3 minutes pass. Then, the box can no longer be seen.

If that’s normal, then that makes no sense to me, and it would fool the programmer, yes?

Could you please adjust the capacity and/or activeParticleCount… in a way that the particle density would APPEAR consistent across time? (thx) Then maybe I can grasp it. (sorry for the hassle, DK).

I just can’t see the usefulness of a particle system that changes particle emit-density over time.

But if emitRate is based-upon (a percentage of) the total particles in the pool, THEN it makes sense. The emit density WOULD increase as the pool filled… then. But if true, I’m not sure percentage-of-pool is a good way to calculate emit rate.

Thx for hand-holding me for this, DK, nice of ya. Wingnut seems to be a perma-puppy in some/many ways.

Good Q&A sweep-up… this morning, too, thx for that. I tried to do a little weekend Q&A work, but most of the questions were too advanced/difficult for me.

[Deltakosh]

I don’t know how to say it differently. The emitRate is the same… It does not change. You just see more and more particles as the emitRate accumulates more particles on top of the previously emitted ones. So you start with say 10000 particles in total and after a while you have 1000000 particles. No wonder why it is more dense

Just set the capacity of the GPU particles to a smaller value.

here is what I see after 10 minutes:

10000000 particles… all good

[Wingnut]

Nod. Ok, thx. Same look here, after 10 minutes.

It’s just… alien to me… a system yet un-learned by Wingnut. You’re explaining it fine… I suspect. I think I have a root misunderstanding of emitRate and lifetime/age. thx agn.

[Deltakosh]

yeah I think this is just a misunderstanding. Maybe emitRate should have been named: Number of particles ADDED per frame

[Wingnut]

For fun, I tried a kludgy “compensator”… https://playground.babylonjs.com/#PU4WYI#109 lines 79-81.

.minLifeTime goes far negative. I have never tried that demented act before. Fun! Box stays visible MUCH longer.

Negative minLifeTime values? Hehe… potential explosion nearby, eh? Fun, though.

I think this will cause the particle system to almost die, eventually.