Ok.. I've been playing at trying to make some more realistic fire with the particle systems. After a few days of studying, I got some ideas and came up with this.

http://www.colins-loft.net/free/examples/s...tCompressed.mov

sorry for the large file size, but I wanted to discuss the details, so I had to compress a little less than I might normally.

So after creating this and studying the effect.. I find several things that could be improved in the sprite particle system. Heres the list. I'm not demanding these of course.. just suggestions to blow the top off of the effects.

1. It would be nice to be able to randomly start at different spots in the animation.. on animated particles. This would go a long way toward getting rid of some of the repetition in the effects. You can see a definite pattern in the fire above. This is do in part to the animated sprite always being on the same frame.
   
2. It would be nice to be able to have a sprite be able to be randomly flipped at its birth so that you could get more variation in shape without having to create two emitters.
   
3. It would be nice if you could control the color of a sprite over its life by using a gradient, similar to the random color gradient, but allowing the sprite to begin its color at the left of the gradient and smoothly transition toward the end of the gradient over its life. This is similar to many other particle systems out there and would allow for more fine control I think.
   
   A side note on this one.. it should be able to control the particle color over time as it is now.. but I can't seem to get it to work. Any suggestions?
   
4. It would be nice if there where a few more options for the rendering of the particles. ie... Only on the last pass of a Multipass render, allow for particle variation or "Jitter" in a multipass render, etc. I know those two are mutually exclusive, but what I'm saying is that "better" effects could be achieved if we had this
   sort of fine control.
   
   The example above took 10 hours to render on a "normal" render without multipass. Not to bad considering, but imagine the render times with a full scene and multiple particle effects. With the ability to just render particles in the last pass and not be forced to anti-alias them when they don't really need it, the render times could go down dramatically with no loss in quality. The sprites themselves are antialiased and render fine without needing a second pass at AA most of the time.
   
5. There seems to be some sort of cyclic pattern to the birth of particles. You can see this in the left to right emission and death of the sprites in the fire above. I couldn't find a way to control this or "tone" it down. It would be nice to be able to randomize it more, though this "effect" has its uses as well, so I'm not asking to lose it... just to have another option for the emitting pattern.
   
6. Now I'm getting picky... It would be nice to have more options for layering particles, beside Add and normal. I can imagine some interesting effects that could result from Overlay, Multiply, Invert, etc. On top of this.. Something that would greatly improve Fire simulations is the ability to subtract One sprite from another, ie ... sprite layering order. This would allow for more variation and a more organic shape to multi-sprite systems.

I think that the additions mentioned above would allow for a system that could do just about any type of pyroclastic or particle effect. Does anybody else have other notions for improving the sprite emitters or particles in general.

So I know this is the "stability edition".. and believe me I'm all for that, but its also the TWO edition, and these improvements would make the particle systems, exponentially better, and therefore the effects in TWO.

comments? Suggestions?

C

*Ken ducks while the fireworks fly*

Nice fire....though you can see the repitition.

I hesitate replying to this because I honestly didnt grasp all of your post, wish I did and I know there are others who will....but if Im understanding correctly these additions would have to come in at the programing end? or maybe a plugin programer? All the suggestions do sound interesting and maybe can be implemented someday, but what happens if they (the programers cant get to it in time for TWO effects wrap up? . So Im guessing Im asking ,how far can one push it with the way spriticles are now? how worried should one be about render times?
Also. is there a way of mabe combining Sprites with Streaks? streaks use to be the fire and smoke of some of the past versions, Ive experimented withit but that was awhile back when sprites where first intoduced to AM.
Anyway, Im looking forward to how this all turns out, I love special effects and the more realistic the better..............the clip does have the obvious cyclic look...
Also.. the only thing I know that can be done is having a series of animated images used for sprites........

Michael

We can still push allot, but it means a few things. It will take allot of "tricks" to fix these things, and the end result might not be as good as we'd like.

Render times can be worked around. We could separate the renders into a particle Pass and composite the particles back into the scene in post (Something we might do anyway in some shots), but those introduce other issues that we'd have to work around.

All of the things mentioned above have more to do with the quality and speed of Producing an effect versus, Its "this way or no way". With a few more things to pin the above fire into a scene and some lighting to make it believable.. it could be very realistic in short cuts or perhaps even longer scenes. I think with a few tweaks to the engine though... It can be brought to a level acceptable for "Cinematic" effects.

The thing I liked about Shrek, is that the characters seemed more animated, because they where stylistic, which allowed for more expressive animation, but the effects and scenery where very realistic which made the characters more believable.

This discussion is completely open to dissenting opinions, and I'd like to air it all out here in order to come to a consensus... So fire away ;-)

C

C

If you bring-up the TIMELINE panel, and set it to channels mode, It will allow you to show % when setting color properties for the sprite[set color to "Over Life"]. Similar to how you set hair properties along the length %. If that isn't working, It may need to go to A:M reports.
Similarly, I avoid the "popping" issue withe the sprite appearing and dissappearing by setting transparency keyframes over life. 100% at birth--fade up to 0% transparency at 5-10% of life and fade them out the same way.

Yeah I tried that but the percentages didnt show up in Version 11.. I'll try it it 12 and 13 and report it if its not working right.

I am fading it as you say in the beginning and end as well as scaling it up and down.

Thanks,

C

This wouldn't have anything to do with the fire emission in particular but I would add the ability to control object collision and particle collision for each individual sprite emitter as opposed to one switch for the whole sprite system and all its sub sprite emitters. Not a big deal because you can have totally separate sprite systems and independantly control them that way. It would just be nice.

Upon frame by frame and slower playback, the fire looks as though the sprites could use a bigger frame offset or at least a more random one.

I notice that they all seem to start and play the animation the same way, is the frame offset on the sprite animation sequence even set?

One thing to keep in mind throughout this discussion is the fact that we are not going to see the fire/s for an extended period of time in the movie. I would even go as far as to say that the fire clips would be so short that the repetition will not even be noticed by those that don't know it is there, unless they were specifically looking for it. This is not to say that all the discussion on how to make the fire better is for naught, but the fire you've got going there, I'm sure would pass the muster for a background clip lasting seconds at best.

What I'm trying to say is: Colin, you did a great job with the fire in my humble opinion.

On

I'd say just, make the emitter more random in shape like hills and valleys and the angle of the slopes will cause the sprites to emit in a more broken up way. To take it farther, you might animate the emitter to undulate or oscillate a little as it emits. That should mix up the points of emitting more... or even getting it to spin slowly. Or all of these together can be controlled via pose sliders.