Particles not working...

Anyone have any idea why a particle system would continue to burst at max speed, effected by wind, despite changes to the burst rate, and no call for wind_mask?

default {
     state_entry() 
     {
          llParticleSystem( [
        PSYS_PART_FLAGS,
        PSYS_SRC_TEXTURE, "FOG420",
        PSYS_PART_EMISSIVE_MASK,
        PSYS_SRC_PATTERN,
        PSYS_SRC_PATTERN_DROP, 
        PSYS_PART_MAX_AGE, 0.5,
        PSYS_SRC_BURST_RATE, 5,
        PSYS_PART_START_SCALE, < 0.01,0.01,0.01>,
        PSYS_PART_END_SCALE,  < 0,0,0>,
        PSYS_PART_START_COLOR, < 1,1,1>,
        PSYS_PART_START_ALPHA, 0.75,
        PSYS_PART_END_ALPHA, 0.0
    ] );
}

}

You don't actually *set* a PSYS_PART_FLAGS, which pretty much invalidates your whole call, since the parameters are then in an incorrect order. You need an integer (bit-flag mask) after PSYS_PART_FLAGS.

Also, PSYS_SRC_BURST_RATE must be a float. So write it as 5.0.

ETA: Oh, I see you have a PSYS_PART_EMISSIVE_MASK mixed in there. Move that up where it belongs, after the PSYS_PART_FLAGS.

And then this gives me a script error about the start color.

default {
     state_entry() 
     {
          llParticleSystem( [
        PSYS_SRC_TEXTURE, "FOG420",
        PSYS_PART_EMISSIVE_MASK,
        PSYS_SRC_PATTERN,
        PSYS_SRC_PATTERN_DROP, 
        PSYS_PART_MAX_AGE, 2.0,
        PSYS_SRC_BURST_RATE, 5.0,
        PSYS_PART_START_SCALE, < 1,1,1>,
        PSYS_PART_END_SCALE,  < 0.0,0.0,0.0>,
        PSYS_PART_START_COLOR, < 1.0,1.0,1.0>,
        PSYS_PART_START_ALPHA, 0.75,
        PSYS_PART_END_ALPHA, 0.0
    ] );
}

}

Try:

default {
     state_entry() 
     {
        llParticleSystem( [
        PSYS_SRC_TEXTURE, "FOG420",
        PSYS_PART_FLAGS, PSYS_PART_EMISSIVE_MASK,
        PSYS_SRC_PATTERN, PSYS_SRC_PATTERN_DROP, 
        PSYS_PART_MAX_AGE, 2.0,
        PSYS_SRC_BURST_RATE, 5.0,
        PSYS_PART_START_SCALE, < 1,1,1>,
        PSYS_PART_END_SCALE,  < 0.0,0.0,0.0>,
        PSYS_PART_START_COLOR, < 1.0,1.0,1.0>,
        PSYS_PART_START_ALPHA, 0.75,
        PSYS_PART_END_ALPHA, 0.0
    ] );
}
}

You still need the PSYS_PART_FLAGS in there. PSYS_PART_EMISSIVE_MASK is a parameter to PSYS_PART_FLAGS, and has to immediately follow it.

Edit: See Meade's version.

That's because you don't have PSYS_PART_INTERP_COLOR_MASK set. You ought to set PSYS_PART_END_COLOR as well.

And to clarify Rolig's comment, you need:

PSYS_PART_FLAGS,
PSYS_PART_INTERP_COLOR_MASK | PSYS_PART_EMISSIVE_MASK,

Awesome, that works much better.

The only other thing I wonder is if there's any way to apply "gravity" to the particles, so they fall?

You should check out the Particle Laboratory - just search/places for it. Tons of good info on how particles work, what the various settings do and starter scripts there..

Two thumbs up.

PSYS_SRC_ACCEL, < 0,0,-9.8>

If you want them to fall under 1 gravity. It's common to use a smaller acceleration... it may not be realistic but it looks better in many cases.

For smoke or buoyant particles, you'd give them a positive acceleration.

I always just start with this one:
http://talirosca.wikidot.com/particle-script
and work my way through each parameter, setting the values I estimate are correct, and then fine-tune from there.

Alright. Thanks everybody. Should get a nice little effect out of this.