View Full Version : Particle help!

08-16-2010, 02:52 PM
I've made a spaceship with about 25 particle emitters witch do the exact same thing. It's pretty tedious to change the settings on each one, so the logical answer would be to save all of them as a motion, right? but then I can't change the frame the particles start on, and so if there were to be a battle scene, It would have to start immediatley (the particle emitters are for onboard cannons) or the ship would have to go around with it's weapons systems firing all the time! is there an non tedious way to have just one motion in one emitter and you can change the settings?

08-16-2010, 04:00 PM
I would setup your particle emitters after you've finished animating everything else. This way you only have to set them up once.

08-16-2010, 04:06 PM
You misunderstand me. The scene is a rig that I load onto other scenes for use. the start frame is by default 0, but I need to change it when I load it to a new scene. What I do now is change all 25 start times, but I was just wondering if there was a quicker way.

08-16-2010, 04:08 PM
Ah ok. Well I guess you could change the one emitter and just copy that emitter and parent it to where it needs to be.

Unfortunately the Start Frame value isn't something you can tie to a control object.

08-16-2010, 04:23 PM
Uh ok.

08-16-2010, 05:35 PM
Well, in first place, instead of saving the particle motion and loading into the other particles, you could just change whatever you need in the first emitter, go to the FX_Emitter properties and File/Copy, then use the Cursor Up/Down keys to switch emitters and press "File/paste" Still a bit tedious but would just be a matter of pressing (down key) and clicking "paste" 20-something times.

An advanced option would be to set it up with expressions. Use the first emitter as the main controller. Put envelopes in everything you need to control. (for example, "Birth Rate", so that you can control the "start frame"). Now setup expressions so that all the emitters "particlefx.birthrate" will get the value of the first emitter's "particlefx.birthrate". Do the same for all the options you want to control. So now everytime you changed any of those parameters all the others would also change.

Another option, similar to the former, would be to assign a slider to control those parameters. You would still need the expressions to link the slider to the parameters, though, but you would have some interesting control....

Well, I never tried this, but I think it works... at least it worked in the small experiment I made, even if it only had 2 emitters (the second following the first one in behavior). The simulation has to be calculated each time you change something, and that could take a while with so many emitters.

08-16-2010, 06:17 PM
I don't quite understand... I've only used lightwave for 1-2 years...

08-16-2010, 07:47 PM
Well, I think my first paragraph is pretty straightforward. The rest is a bit advanced, but nothing you can't do after reading some instructions and tutorials about how to use expressions and/or sliders.

Good luck with that!

08-16-2010, 07:52 PM
Alright, I kind of get it...

08-17-2010, 08:52 AM
You can also start the particle emission using collisions. This means you have to add collision objects around your scene and if you want different emitters to fire at different times and they after close together life gets ugly real quick. In fact much worse then adjusting start frame by hand.
One other thing you can do is write your own custom particle plugin or expressions giving you gui control of when you start emission. I have seen people do this. But in my opinion this is stupid as you're just changing one panel for another. The one advantage is you can have all emitters start grouped together in one panel or with one slider group.

08-20-2010, 08:36 PM
thanks aurora. I've fixed the problem, so I don't need any help. my regards to Wes.

Mr Rid
08-20-2010, 09:27 PM
If I understand your setup, I think the quickest way to change start frames is to have the baked emitter playback mode set to "key" and just make a keyframe for the emitter (or select mutliple emitters) on the frame you want emission to begin. The emitter animation will start again for each additional key if you want a cannon to fire more than once.

08-21-2010, 09:34 PM
I don't quite follow you... but I made a different setup, so I won't be having any problems.

Mr Rid
08-21-2010, 10:32 PM
-Save Motion on emitter,

-Set Playback Mode to "Key",

Now, for example, if you keyframe the emitter on frames 7, 22, and 51, then the saved emitter motion will start on frame 7, repeat on frame 22, and again on frame 51.