Particle Question

i've been looking and asking around but i can't find an answer. can anyone tell me what PSYS_PART_PATTERN to use to make a flat disk of particles like the top of a cylinder? actually i want the particles to appear randomly in that disk without shooting out from the center or appearing above or below the disk. so far nothing i've tried works. any help is much appreciated.

also.... does anyone know what it means when your script saves just fine then when you try to start the particles you get a message from SL like a logon notification saying "PSYS error: rule #1 unknown"? that's not exactly it but it's close.

thanks!

You want PSYS_SRC_PATTERN_ANGLE, with (I think, experiment) an inner angle of 0 and an outer angle of TWO_PI. You will also want to set PSYS_SRC_BURST_SPEED_MIN and PSYS_SRC_BURST_SPEED_MAX to something very small like 0.001.

The error is probably because there is an error in the list you are passing to llParticleSystem.

thanks Wednesday, that's the shape i want but it looks like PSYS_PART_PATTERN_ANGLE wants to shoot particles from the center towards the edge. i want it to create them randomly in that disk kinda like PSYS_PART_PATTERN_EXPLODE does only in a 2D area instead of a 3D one.

i'm still working on it but i can't find any way to make like a sheet or plane of randomly placed particles. might need to move this to feature suggestions or somethin'.

thanks for helping.

fewer particles, higher speed and frequency, shorter life.

or something. be creative.

that doesn't help at all Mike. higher speed would just shoot them out of the center faster, which i don't want. shorter life would keep them closer to the center as they shoot out, which i don't want. be creative? thanks. i'll also think different, and outside the box. i may leverage a paradigm but don't hold me to it.

Set an almost zero speed, and set the burst radius to the size of disc you want.

I found when making my rainmaker that I had to use 6 emiters in it and rotated each one 30 degrees to get full coverage. Dunno if that will help but since particles are 2D it seems to be the only way to create a 3D effect.

ah Wednesday, we're getting closer. that made a ring and not a disk but almost there. thanks for the push.

instead of telling me what it does, try it and see what happens

I mean, I'm not sayin' I'm right, but I see a solution in what I told you.

adjust the min/max speed so their range forms your disk, and tweak till it looks right. That's what I'd do.

that's precisely what i did and why i said what i said Mike.

the problem with PSYS_PART_ANGLE is that the particles want to move from the center towards the edges. they are created in the center. high speed means they shoot out faster. shorter life means they die closer to the center, in other words a smaller disk. i want particles to be randomly created, in a disk, at different distances from the center.

giving PSYS_PART_ANGLE a burst radius with almost no particle speed is almost what i want but it creates them all at a fixed distance from the center, not randomly distributed.

i don't know much yet but i do know enough to try something before i shoot my mouth off about what it does.

What you're asking for is, unfortunately, impossible.

I am able to accomplish this by putting a timer event in to update the particle script very frequently then i have the particle script pick a random radius from 0 to the radius I want, its not completely perfect but works fairly well.

cool tip! i know what you're talking about and i'll give that a try. thanks.

the problem with this is that each and every single timer fires, the entire object must be refreshed to all clients within range of it. (particles are object properties after all).

Having a 0.1s timer with a particle script can literally cause about 10k/sec extra bandwidth for everyone nearby, for a *SINGLE* emitter

the actual effect you describe can be very nearly approximated using one of several more advanced tricks.

using an angle_cone effect with a fixed radius, and a small inner-outer angle gives you a section of a spherical surface, within which particles will appear randomly

move the emitter further back, and extend the radius of the particles, while slowly lowering the angles will gradually 'flatten' out the surface over which they appear randomly till it is very nearly a plain disc


another trick i've used to get something like that is rather 'spun out' from the center emitter using just the plain angle, and the object tilted on its side so its 'zero' angle is horizontal. with a radius of zero, have it 'target' itself, and tweak the actual particle life abit, mixed with the min/max speed... with a little practice you can get it to 'appear' like the particles are just kind of popping up randomly within it, or its a rather solid disc, again depending on yer specific settings.


if you would like me to show you these effects in world, or several others i would be happy to, and help point you in the right direction (aka AWAY from object updates)

btw the lindens can and *WILL* take notice if you suddenly cause a large amount of update lag for your neighbors and yourself... i was using a trick like this fo make lightning bugs appear within a specified volume, and kelly linden yelled at me x.x (rightfully so)

thanks for the input Eltee. this is for something that's used far away from anyone and that rezzes when needed then goes away when it's not but i am definitely interested in a lighter solution. i'll give ya an IM.

that's was exactly what i needed Eltee. thank you thank you.