Particle Animation: I want to achieve a bullet-time effect

[drunkirishmic]

this is the beauty of cg, u dont need any fancy tricks to procude this effect. just animate it. when the bullet time starts, just severely slow down ur particle system. no tricks, its cg, u hav complete control.

[yoni-cohen]

or use pflow and store the speed vector to resume motion later on..

[Aldaryn]

The problem with this type of animation is that if you have a particle system emitting particles, there are only complicated ways to slow down every particle, already having some bigger velocity. So if you just animate teh particle speed, the particles already emitted won't be affected, so you will have a fountain going into bullet time, but some particles (The ones already emitted with a given bigger impulse) will just escape the effect, and will produce a wierd result... :(

Suggestions on to du this without using any 3rd party particle system, like the wonderful, - yeah really it is - Thinking Particles, would be to experiment with grawity and wind space warps.
I think putting a grawity into the scene would decrease the speed of particles evenly, and that is the key point, even speed decreasement. So it is the gravity object that is to be animated instead the particle system it self.

But IMO the best way to do this, is to render the animation until it goes into bullet time, create a snapshot of the mesh of the fountain, and do the round camera motion with the "frozen" world in another pass, then render the rest of the fountain animation. Later it could be composed together in every compositing, or video editting program, or even in MAX's built in compositor, the Video Post.

Good luck!

- A.

[Aldaryn]

Originally posted by yoni-cohen
or use pflow and store the speed vector to resume motion later on..

Oh, yes, I've almost forgot, if you're subscribed to discreet, download particel flow, and the problems solved, but that needs some experimenting, and esperience. No other more "discreet certified pluging" in particles can be found right now... :D


- A.

[Simtub]

Wow, thanks for the quick tips guys...you've got me thinking hard about the techniques you mentioned which i'm going to try out.

The effect im trying to achieve is zero movement of the fountain of water, im wanting to make it totally still so slowing down some of the parameters might not be so useful as there wud still be some drag.

i dont have pflow as im not subscribed Cheers:hmm: so I'll experiment with standard max and let u guys know how it goes

[Aldaryn]

IMO if you don't want that typical bulett time effect (Time doesn't stops, but flows, Really slow....) but you're satisfied with a total stop, the compositing type of method is the best, if you don't have Particle Flow, oir any other 3rd party plugin.

Have fun with your work! Really! :D

- A.

[Dave Black]

Just realized my post was redundant. Edited to make me look less like a moron.

-3DZ

:D

[JayCMiller]

Just another way, & it's prity slow but another option.

animate your camera to how you want it, and then clone the camera as many times as there are frames (for the frozen part). next shift the cameras' keyframs back & you'll have them all lined up along the motion path. finaly render each camera at the same frame (see above brackets) & comp.

Particels are the only thing that I imagined you would need this technique for but it seams from the other posts with the right tools you don't need it.

[Aldaryn]

JayCMiller: Now this is something wicked, man! Doing it like the original real life bullet time is done! Cool!

This is the absolute mimic of the real world. I just turn my head away for a while, and the nex thing will be modelling true green boxesaround your scnene, instead of alpha channels.

Cooool, yeah! :buttrock:

[Reality3D]

You can try with this(but is in spanish).

http://www.3dyanimacion.com/tutoriales/tutoriales.cfm?estado=ver&titulotutorial=El%20efecto%20Matrix&codigo=3&tutorialID=16

[JayCMiller]

that was the idea Aldaryn.

how'd you know about my Alphas?:p :D

[Steve Green]

If you download pointcache2 from http://www.footools.com, you could use a mesher object referencing the particle system.

Record the point cache on the mesher object, then you can keyframe the playback so that you can freeze the object, or reverse the motion if you want.

- Steve

[Reality3D]

That's a good tip Steve!!

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