Page 1 of 2

RF4 Fire Simulation

Posted: Tue Aug 07, 2007 3:47 pm
by MightyG
Hey guys,
So everyone that has seen the Nextlimit fire "tutorial" knows how broken it really is. Ive seen some impressive looking fire particle simulations on others sites that use RF4 and not Sitni Sati's FumeFX. Ive done alot of attempts and it and asked Mark Stasuik himself for help but its "trade secret" info so does anyone have progress in this department?

RF4 Fire Simulation

Posted: Tue Aug 07, 2007 4:14 pm
by Chman
Not sure that this post will help you, but...

You could take a look at Navier-Stokes equations, well known in this department for their speed & efficiency. From what I know, FumeFX use them extensively. Make a search on Google about Navier Stokes and fluid solvers, you'll find a lot of articles and example (even realtime examples).

Using Navier-Stokes equations would require a lot of scripting though and might be a bit slow (python is not that fast). Also those solvers are grid-based, which might be tricky to setup in Realflow but not impossible.

Tom

RF4 Fire Simulation

Posted: Tue Aug 07, 2007 5:55 pm
by MightyG
wow i just spent the last hour reading really complex calculus haha. Its nice and ive seen some great results.

RF4 Fire Simulation

Posted: Tue Aug 07, 2007 9:21 pm
by MightyG
So if anyone follows this thread, im going to attempt to bring the infamous fire sequence to the masses. From what i understand I have to calculate particle interaction with outside forces. How Mark S. did it with Daemons befuddles me. But Ive achieved a nice looking sim by doing it the heavy way. Create a box filled with liquid particles, no gravity, add your emitter and shoot it into the box. Create an age deamons etc. etc. ill put up a clip tonight.

RF4 Fire Simulation

Posted: Tue Aug 07, 2007 9:34 pm
by Chman
MightyG wrote: How Mark S. did it with Daemons befuddles me.

When you look at an explosion or big amount of smoke coming from a tower, you can see lots and lots of condensed vortex... I think it could be possible to do it using vortex daemons.

But Ive achieved a nice looking sim by doing it the heavy way. Create a box filled with liquid particles, no gravity, add your emitter and shoot it into the box. Create an age deamons etc. etc. ill put up a clip tonight.

Can't wait to see it !

Tom

RF4 Fire Simulation

Posted: Wed Aug 08, 2007 12:42 am
by MightyG
So i spent some time writing a daemon script and playing with scene settings and this started to turn into a bubble sim kind of. haha

http://www.youtube.com/v/nQOs2o3zgLw

RF4 Fire Simulation

Posted: Wed Aug 08, 2007 2:19 pm
by markstasiuk
Although I think you could take the approach of solving the navier stokes equations, I'd say good luck and see you in a few years. Even using simplified versions, solving for the behaviour of a turbulent, expanding fluid has been a long-standing challenge in the academic community. In any case, the beauty of rf is that it does most of the calculations for you, you just have to figure out what's missing and nudge the fluid to make up the difference.

I'm interested to see what else people come up with on this.

And where's this fire tutorial of NL's?

RF4 Fire Simulation

Posted: Wed Aug 08, 2007 3:46 pm
by shaun_michael
Hi Mark,

Its not a tutorial as such but you'll find an example scene http://www.nextlimit.com/realflow/te_scenes.htm

Shaun

RF4 Fire Simulation

Posted: Wed Aug 08, 2007 5:25 pm
by Spongebob
Ooohhh I like the starting of your fire script. That has been the one little spot I have been trying to refine in my fire simulation is the initial firing up. And I can just imagine what that would look like meshed with a material on it! Cool!

I wish I knew the scripting a little better than what I do, and could come up with that too!

Take a look at my flame, and you'll see what i am saying about the initial starting of the sim and how your script would be great there...I think:)

My Candle Flame experiment comp.

Around the 33 second mark is the starting that I like the best. But it need to be better!

RF4 Fire Simulation

Posted: Wed Aug 08, 2007 5:49 pm
by MightyG
some updates. Each sim took about 10 minutes so they arent the best.

Anyways, various experiments with the Navier Stokes ideas NOT using scripts but ANIMATING properties. Once i tune it ill script it.


http://youtube.com/watch?v=0qfInJLo3BY