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Carm3D
02-25-2009, 08:31 PM
Hi..

I've been tinkering with HV sprites lately trying to get realistic fire.

Here is my first test: YouTube Link (http://www.youtube.com/watch?v=JCEW8x0f0BY), Vimeo (http://vimeo.com/3073205)

I made little particle explosions in Vision for the sprites.

Then, for this test (YouTube (http://www.youtube.com/watch?v=is6Fc-xti1U), Vimeo (http://vimeo.com/3374435)) I made the sprite from a single HV blob that deformed. I think it's much closer. I also used exaggerated motion blur (200% length) to make them look more streaky. It helped alot but I've seen much better fire from other artists...

Any suggestions?

P.S. particle motion generated with the Fire & Smoke plugin.

prometheus
02-25-2009, 09:47 PM
Well..I think they are to blobby, so try and select a proper hypertexture..
like the turbulence texture..and make sure your hypertexture value is enough to cut throu the blobby volume..so you might need to increase that value..
Thats for starter..but thereīs more to it than that.

http://vimeo.com/user680656/videos/sort:date

Michael

JMCarrigan
02-25-2009, 09:55 PM
Cool stuff prometheus.

Carm3D
02-26-2009, 02:17 AM
I want to try to achieve an effect where the lick of fire starts blobby but then 'ruptures' into a more turbulent look at the end. That will be my next test.

mattclary
02-26-2009, 08:08 AM
Anyone know of any good smoke/fire tutorials? Not finding much that seems useful.

dandeentremont
02-26-2009, 12:46 PM
Check out this scene (attachment) it's 9.6
I find one of the most important things to make nice fire is to make the center of each voxel dark and the edge bright.
If your computer can handle it, i would suggest using volume instead of sprites for fire. They just plain look better :-)

Stooch
02-26-2009, 12:55 PM
fire effects are pretty involved. ill have to make a tut sometime but ill make it brief here:

key to fire is your texture. i like to use crumple or turbulence with animated texture time, i like to overdrive the texture value towards the start of particle life time and then fade out the texture towards the end.

your luminousity should be driven by both particle life and a density curve. higher density = more glow.

same goes for color. your colors are inadequate here. look at footage of fire for reference.

do not use lights to illuminate your fire. fire is self illuminating, so all you need is luminousity.

fire particles gradient should start at 100% scale and grow to 400-500% depending on the lifespan of the particles. use the random voxel size to taste.

you should scale them up so taht they overlap and blend with each other. DO NOT overemit particles, you need to balance the number of particles with particle size.

use particle velocity stretch, i like to sometimes use particle life in conjunction with particle speed. so that they kind of stretch very briefly durign the early stage of their life and then return to no stretch state.

your particles should always have a negative gravity setting... fire goes up....

your particles should have a random velocity, random mass and random resistance. a uniformly moving spread of particles will never look like natural fire.

turbulence is useful for fire. fire doesnt just always go up. it creates convection currents which cause fire to spiral and or boil as it moves up.

you must get your animated texture speed perfectly. again.. observation.

use viper to tweak your fire.

no need to press f9. just open viper, open voxels, click on voxel and set viper to mosaic.

TWEAK TWEAK AND TWEAK. spend an entire day just adding one step at a time.

spend couple of hours with just particles and get them to move in a way that reminds you of fire.

THEN add voxels and play with scale. DONT add any BASIC channels, just work with your crumple or turbulence procedural to get it right.

THEN add other channels ONE at a time. if you add too much stuff you will get confused.

again. the key to fire is observiing footage of fire. or start a fire and stare at it as it consumes all.

p.s. pretty much ALL channels in your settings should be driven by gradients driven by particle life..

dont be afraid to set density over 100%! it really helps you make things pop and look bright (especially when using luminousity driven by density)

transparency is a tricky channel, the more tranpsarent your voxels are, the brighter they look.

in the case of a fire, you should never have 100% opacity on any voxels at any time. i like to start at ~75% opacity and fade out with life time.

anyway there is ALOT to it, i think making a vid is in order.

mattclary
02-26-2009, 01:12 PM
Thanks, Stooch!

Stooch
02-26-2009, 01:16 PM
you are welcome! its a little daunting at first because there is lots of things that mus interact for it to look right, but its really fun ;)

one tip to using viper is to time it in your head and then skip frames. IE i would skip 1 second at a time and let viper update to get a mental timing of my fire. you really need to get used to doing it this way or you will spend alot of time rendering :)

this is a super critical part of animating effects! what looks good on the first frame, wont necessarily look good on the last.

also make sure to use motion blur, dithered and enable particle blur. also be aware that particle blur sucks, thats why there is a particle "stretch" value.

also be aware that you can render particles at half res with no AA! (i still use little bit of AA just to get some motion blur on my hold out objects).

oh yeah, if you are using a particle streamer. meaning a trail of particles being emitted from a moving emitter... you need to set your motion blur to a negative value! ie -50% otherwise ther will be a gap between the emitter and the particle trail (particle blur in LW SUUUUCKS)

did i mention that lw particle blur sucks? well... it SUCKS. because it only factors in the movements of the camera! not the particles themselves. most of the time you can kind of work around it but there are time where things move past camera extremely fast and you will get UGLY results. the trick here is to shoot particles in a way that allows the emitter to blow by camera while keeping the particles themselves at a reasonable velocity relative to camera.

this needs to be seen for yourself for you to truly appreciate what i mean.

OnlineRender
02-26-2009, 01:23 PM
easier way would be to use particle illusion there a 30 ultimated try download , view the results on my page . www.youtube.com/onlinerender

Stooch
02-26-2009, 01:27 PM
umm... its easier... but... eww. sorry. lol.

Andyjaggy
02-26-2009, 01:28 PM
Well Stooch pretty much summed it up nicely. I'll throw in my two cents, I'm no fire expert but this is what I have found works pretty well for smoke.

I render out two passes. A sprite pass and a volume pass, and comp these two together in post.

I usually use the crumple hypertexture with the mode set to billowing.

Lots of gradients based on particle age.

Donut winds and vortex winds seem to give me the best looking movement for the smoke.

Only adjust one parameter at a time. If you change multiple things for every render sometimes it is hard to tell which one actually gave you the change you were looking for.

Stooch
02-26-2009, 01:30 PM
eh. crumple seemst o work OK but dont you find it makes things a little too...blobby? i guess it might be good for sparks.

i find that turbulence set to billow or turbulence to be the most realistic texture for fire. but at the end of the day you just gotta use whatever matches the reference best :)

mattclary
02-26-2009, 01:40 PM
i find that turbulence set to billow

Ok, WTF? "Turbulence set to billow"? I see turbulence for wind (under Mode), but no setting for "billow"... What am I misunderstanding or not seeing?

Andyjaggy
02-26-2009, 01:43 PM
Hypertexture panel in hyprvoxels. You get a bunch of options for the texture effect, one of them is billowing.

I haven't used it for fire, I was just referring to smoke, seems to work okay for me, I'll try turbulence next time.

JeffrySG
02-26-2009, 01:46 PM
Well..I think they are to blobby, so try and select a proper hypertexture..
like the turbulence texture..and make sure your hypertexture value is enough to cut throu the blobby volume..so you might need to increase that value..
Thats for starter..but thereīs more to it than that.

http://vimeo.com/user680656/videos/sort:date

Michael

Those are some very cool animations.... :thumbsup:

mattclary
02-26-2009, 01:46 PM
Ahhhhh, OK. Awesome.

JeffrySG
02-26-2009, 01:47 PM
fire effects are pretty involved. ill have to make a tut sometime but ill make it brief here:

key to fire is your texture. i like to use crumple or turbulence with animated texture time, i like to overdrive the texture value towards the start of particle life time and then fade out the texture towards the end....

...anyway there is ALOT to it, i think making a vid is in order.

Cheers Stooch! I don't really do animation much but this is great to have! I'll have to work on it one day. :)

dandeentremont
02-26-2009, 03:02 PM
K I got a scene like the one before but with volume instead of sprite.
Here's a comparison:
http://i294.photobucket.com/albums/mm109/papalive/sprite_volume_compare.png

Carm3D
02-26-2009, 03:15 PM
Wow.. What a difference!

Steve Kaplan
02-26-2009, 05:26 PM
fire effects are pretty involved. ill have to make a tut sometime but ill make it brief here:

Thanks so much for sharing Stooch. :thumbsup: I've had first hand experience with your HV setups and can attest to how well they work. Not only visually, but in a production setting.

I agree .. you should set up a tutorial. I'll be copying your post down for my own reference.

prometheus
02-26-2009, 05:53 PM
I actually prefered the fire you posted 3 weeks ago on youtube..it feelt more like natural fire in terms of texture type and size, but the color range and shading could be improved on that one with gradients.

Thereīs of course different type of fires as explosions etc..
the kind of type you seem to acheive is probably one of the hardest to do..especially with particles.

I guess your after that more of a big flame style? wich has that gasoues depth look with glowing edges and deeper darkness inside of the fire volume.

The fluids in the plugin dynamite could do this so very sweet..but we all now the story about that one donīt we?


otherwise when you look at most fire they are very white and bright with fast flames..at least for bigger fireplaces, the flame style seems to accour at a smaller scale like when lighting a piece of paper, I guess it depends on what kind of material is burning and fuel etc.

then thereīs fire that only burns fast and shortly just to die of in a burnt soot and smoke pillars, like a house on fire.
preferably we need maybe several emitters for a better result.

Ohh as always.. search up the threads of Mr Rid if you would get an idea of how to work with fire, and remember itīs not easy, takes time practice and most often post work.

Ohh and check your youtube for fire clips, or get out and film some stuff of your own..and analyze.

Michael

prometheus
02-26-2009, 06:36 PM
Thanks so much for sharing Stooch. :thumbsup: I've had first hand experience with your HV setups and can attest to how well they work. Not only visually, but in a production setting.

I agree .. you should set up a tutorial. I'll be copying your post down for my own reference.

Yeah stooch and while youre at it, It would be nice if you could write tutes or do technical breakdown descriptions on setting up massive particle
and missile projectiles and targets and how you go about it? if you can reveal the secrets:)

Michael

Carm3D
02-27-2009, 03:39 AM
do not use lights to illuminate your fire. fire is self illuminating, so all you need is luminousity.

I turned off ambient and lightsources.. But even when I crank up the luminosity to ridiculous levels, my volume HVs are always solid black. :(

prometheus
02-27-2009, 03:57 AM
I turned off ambient and lightsources.. But even when I crank up the luminosity to ridiculous levels, my volume HVs are always solid black. :(

Solid black strange?...strange! you shouldnīt turn of your main light.
also you can increase the hypervoxel ambient light, raise the smoothing option a little bit that helps brighten it up sometimes.
Opacity at 100 % will block lights out...pull it down to let light pass throu
the volume..that is if you have a main light..but be careful it takes longer
time to calculate with low values since the light passes throu the whole
volume.


Hmm not sure about that one..stoochno lights to illuminate fire?..well depends on I guess, if you are using sprites, correctly lights are of no use, but
for volume..well you can get a different illumination that scatters light inside the volume if you are using a light at the bottom of your fire and use
the rayleigh mode, but it can be hard to tell the difference, it depends on how you set the shading up otherwise, it isnīt really that neccessary..however for explosions and for rocket/missile trails I believe that a light parented to the center serves the illumination well, also the light also function to light up other objects in the scene.

Michael

shrox
02-27-2009, 04:16 AM
I have stolen the scene and I am going to use it. Well as a starting point anyway, your flaming talents are quite nice.

Carm3D
02-27-2009, 04:38 AM
Would be nice if lights could be attached to particles.. Even given a relative particle age to vary the light's colour and intensity... Maybe in Core? :)

IMI
02-27-2009, 05:35 AM
Wow, what a tremendously informative thread here! :thumbsup:

prometheus
02-27-2009, 06:02 AM
Would be nice if lights could be attached to particles.. Even given a relative particle age to vary the light's colour and intensity... Maybe in Core? :)

Well I believe thatīs what Dynamites voxels could do..with ray emission and itīs internal fire engine, not exactly attaching light, but emitting light.

so the whole Dynamite internal fire shader, and dynamites metaball functions on polys should really be copied over to hypervoxels..But the hypertextures are doing fine..I prefer them over dynamites .

The fluid stuff is another story..

Michael

Carm3D
02-27-2009, 06:09 AM
Well I believe thatīs what Dynamites voxels could do..with ray emission and itīs internal fire engine, not exactly attaching light, but emitting light.

Nah nah... It's gotta emit light to the environment!! :)

IMI
02-27-2009, 06:45 AM
Would have been nice if somewhere along they way they could have been bothered to make VIPER multithreaded...

Anyhow, I always thought you *had* to use particles or HV emitters to get these kinds of effects, but the "HV Custom Object" is a whole lot faster to render and easier to deal with.
Thanks again, dandeentremont! :thumbsup:

IMI
02-27-2009, 06:49 AM
OK, now I'm confused. It is in fact an FX emitter. Yet it only shows up as a Null, not an emitter. What's the difference?

EDIT:

OK, I see. You can add "HyperVoxelsDrawing" under the Geometry tab to any object, then select Emitter from the Dynamics tab, and the HV's are conformed to your object. Or rather, they "grow" off your object. I really wasn't aware of doing it that way. I thought the only way was to create an emitter and parent it to an object, or a null. Very cool. :)

prometheus
02-27-2009, 08:04 AM
Nah nah... It's gotta emit light to the environment!! :)

Well it illuminates the environment, hypervoxels canīt do that as what I know of.

But Iīm not sure exactly what type of light you mean?

it would be a render clog killer if they were real lights..
Hey you could always read the particles motion path by editing the node
and add a null and then parent lights to that..huh.

heres a screen cap from the dynamite doc...about the ray emission.

Time to go to bed now, even if itīs only in the middle of the day here in stockholm now, been up all night..trying to get something decent with fire sprites...hopefully I could show something tomorrow.

Michael

IMI
02-27-2009, 08:34 AM
Nah nah... It's gotta emit light to the environment!! :)

Since it's luminous, wouldn't it emit light into the environment if GI was turned on? And I suppose you could crank up the GI intensity to light it further, rather than cranking up the luminosity and changing the effect.

Carm3D
02-27-2009, 02:28 PM
That is neat that it can emit GI light.. But if it were actual light sources it would be cooler.. And more directional. The solution to it being a render clogger is to make two sets of particles.. One for your HVs and another more sparesely populated (but with the same general movement) that have lights attached/instanced to them.

Anyway.. Here's another test..

Vimeo (http://vimeo.com/3399998), YouTube (http://www.youtube.com/watch?v=3EP1iOKofXE)

This time rendered as volumetrics instead of sprites. I tried to get the look I had in my earlier sprite version where it was opaque on the edge of the HV and transparent in the thickest part but I couldn't figure it out. :(

IMI
02-27-2009, 02:42 PM
That is neat that it can emit GI light.. But if it were actual light sources it would be cooler.. And more directional. The solution to it being a render clogger is to make two sets of particles.. One for your HVs and another more sparesely populated (but with the same general movement) that have lights attached/instanced to them.


Does LW still have "luxigons" or whatever they're called? I think I only messed with that once, in LW 8. I haven't noticed them In LW since 9.0... haven't looked for them either.
But I would think you would need a whole lot of different, animated lights to create the effect of fire light shining on something, since it's constantly changing in direction and intensity. I would think GI would be the easiest way to fake that.

Your fire test video looks pretty good. Much better than my attempts at least. I got some really good results animating fire using dandeentremont's files... but that's cheating. ;)

Carm3D
02-27-2009, 03:02 PM
Does LW still have "luxigons" or whatever they're called? I think I only messed with that once, in LW 8. I haven't noticed them In LW since 9.0... haven't looked for them either.

Yeah... it's still got those.. It wouldn't help for what I am prattling on about..


But I would think you would need a whole lot of different, animated lights to create the effect of fire light shining on something, since it's constantly changing in direction and intensity. I would think GI would be the easiest way to fake that.

If a light instancing application would allow us to use a gradient for the lights colour and intensity based on the relative particle age.. It would be equally easy. And more visually striking than GI.. I know because I faked this one time. Without the aid of said gradients. It was very tedious but the end result was very impressive.. The only light in the scene was from the torch and it looked tres cool as it flickered away. Took a heck of alot of time to set up tho!!!


Your fire test video looks pretty good. Much better than my attempts at least. I got some really good results animating fire using dandeentremont's files... but that's cheating. ;)

Thanks. I will probably add a little smoke next. :)

IMI
02-27-2009, 03:13 PM
Minor correction - you have to make sure "Volumetric Radiosity" is checked in the Render Globals panel for GI to work on HV's. Slow to render, but real nice effect.





If a light instancing application would allow us to use a gradient for the lights colour and intensity based on the relative particle age.. It would be equally easy. And more visually striking than GI.. I know because I faked this one time. Without the aid of said gradients. It was very tedious but the end result was very impressive.. The only light in the scene was from the torch and it looked tres cool as it flickered away. Took a heck of alot of time to set up tho!!!


Well Carm, I'm sure you know far more about it all than I do! I wouldn't know where to begin doing what you say above. I can animate basic things, but HV's and particles are a whole new thing for me. Fun though. :)

prometheus
02-28-2009, 08:45 AM
Hey Carm3d..Try some gradients based on Texture value on the color and lumonosity channels to give it a little more depth perhaps..

tweak and experiment with the hypervoxels texure scale..in combination
with lowing or raising the frequencies values...if your using the turbulence hypertexture that is.

and Try also to set the frequencies value to 0 and control the finer details
only with small power and also balance that with the hypertexture scale.

setting a contrast level within -50 to +50 are usually good.

My computer mouse is giving up on me..have to buy a new one tomorrow
so I canīt tinker with the fire today.

Michael

Andyjaggy
02-28-2009, 12:11 PM
That looks really nice. Good job.

Carm3D
03-01-2009, 03:18 PM
I've nailed it! Thanks for all of your suggestions. Here's the latest:

YouTube (http://www.youtube.com/watch?v=IWEUrbmP-Eg)
Vimeo (http://vimeo.com/3425179) (Better quality)

The local density gradient for luminosity did it (thanks Stooch & Dandeentremont!).. I used that as a multiplier on top of a Relative Particle Age gradient.

IMI
03-01-2009, 03:27 PM
I've nailed it! Thanks for all of your suggestions. Here's the latest:



Looks great! :thumbsup:

Carm3D
03-01-2009, 03:33 PM
Thanks IMI! Now if I can just get the flames to emit light! :)

flashover
03-01-2009, 04:04 PM
Make real fire and smoke is very difficult with LW, LW need same shaders dedicated.

Carm3D
03-02-2009, 06:21 AM
Here's the final version (http://www.newtek.com/forums/showthread.php?t=95905). I added smoke & audio. ;)

prometheus
03-02-2009, 01:11 PM
Well ..I just uploaded some Old simple test done several months ago..I have better stuff soon I think, and probably intergrate it with a proper scene too..

one clip is hypervoxels sprites but uses two emitters to give a little more depth..and itīs more like a little bigger fire..not that slick flame style.

the other clip is a simple flame fire render from basic setups of a dynamite scene..but a little tweaked on the fire shader and swirls etc, If I had the full version myself I could probably get really awesome stuff.
heres the link at vimeo.

http://vimeo.com/user680656/videos/sort:date

Michael

prometheus
03-07-2009, 08:02 AM
heres a little tip on using object emitters and setting emitter nozzle to object line, se images.

an ordinary emitter would emitt particles from the center of the emitter and outwards to itīs whole size, but thatīs not really neccessary, by using this method the all amount of particles are emitted only from the edges of this object and not inside, but since its a circular disc it will appear to have full volume and it gives a nice density anyway, if we were to use an ordinary emitter we would need much more particles to get it to fill in the volume.

also in this case Im cloning the disc emitter..to att a little more depth and fill in of particles.

a little stretching of the hypervoxels on velocity helps too.

The small images with hypervoxels sprites are however directly from
viper..and even only in draft mode, one without blur and the other next to it blurred slightly in after effects.
the bigger pic shows the particles in wireframe.

one wind pulling it up, one wind set to vortex..and changed some scaling on the vectors, and a third directional wind with procedural textures on the vectors to give it small undulations.

Ill render out some clips later..tomorrow perhaps.

Michael

Carm3D
03-07-2009, 08:24 AM
Me thinks the particles need to render bigger.. At least towards the end where you can see them break up.

prometheus
03-07-2009, 08:33 AM
Me thinks the particles need to render bigger.. At least towards the end where you can see them break up.

yepp..I know..perhaps..I usally do that to..I just wanted to show this way.
otherwise Using this technique with a lot of particles without hypertextures should have small particle size and a lot of particles..smaller sizes give a sharper stunning edge to the feel of it, but then again when using blur that will partly be destroyed somehow.

thats around 16500 particles x 2 since the emitter is cloned and then scaled a little to be bigger than the other emitter.

Ahh..Core has a the ability of high poly instancing..please..please..invent
a hypervoxels particle interpolator to create massive million or billions of hypervoxels sprites that doesnt..need to be calculated in the first draft..
Something like the krakatoa type..yummy..

Michael