The Quest for REALISTIC FIRE

Greetings fellow Blenderheads. I am not here to whine. I’m going to make some realistic fire even if it kills me. I’ve already done a lot of work over the past 3 days. You are all invited to help me. When I completely solve the problems I’m faced with I promise to make the MOST definitive video tutorial for realistic fire in Blender the world has ever seen.

Here’s what I KNOW:

  • Cloud textures are three-dimensional. Multiple planes mapped to the same coordinates will act as a single “volume”
  • Halo materials don’t follow this rule - which makes me very sad. :frowning:
  • Fire behaves like a fluid. The base mesh really should be generated by the fluid simulator.
  • The fluid sim system does not have the ability to delete fluid particles after a certain period of time. They’ll need to deleted by other means.
  • Jahka’s new particle system offers a lot of new options that are useful…
  • Billboard particles (do not yet support control over size)
  • (Does not yet allow control over transparency)
  • Does support child spawning - which is good for embers
  • Fire distorts distorts images behind it. Heated air has a different IOR than cool air. I read somewhere that number is lower than 1. That isn’t possible since the IOR of a complete vacuum is 1. We need to find that value.
  • Radiosity can be applied to the render - not just precalculated. I have gotten beautiful results from applying emitted light from fluids with the radiosity button switched on. However, it turns the mesh completely white. The best rendered fire effects need radiosity disabled for that material. I tired making a duplicate, but it uses the same mesh, and meshes are bound to materials… So I can’t have BOTH until I figure something out.
  • I seem to have lost the speed of my fluids along the way… maybe it was the addition of the displacement modifier…
  • BUG!!! : Displace materials behave strangely when you enable radiosity rendering.Note:These images are on a temporary server until I get my own server’s FTP access back. So they might disappear.
    http://www.rgbk.org/zombieking/cloud_problem.jpg
    http://www.rgbk.org/zombieking/fire_wip1.jpg
    http://www.rgbk.org/zombieking/fire_wip2.jpg

Note: I had much much cooler looking fire that I worked on all last night, and all this afternoon (left the PC on) but Blender crashed and the autosave failed. sigh

Ouch! But the last image doesn’t look like fire. It looks like a fluid simulation upside down. Thanks for all your hints at the top! Good Luck!

very neat ideas. hope you get further into it. I havent really tried fire in blender ,but I am planning on some real soon the tutorial would help so much.

looking good so far, I’m interested to see how it progresses!

Note: I had much much cooler looking fire that I worked on all last night, and all this afternoon (left the PC on) but Blender crashed and the autosave failed. sigh

I hate that when that happens! At least you know what to do now and can do the same work in less time… if that’s any help.

Hello i love you fire style, i had try to find a different style off fire and your idea is very cool. Soon i post my results.

One physical difference between fire and an upside down fluid is that flame diminishes in volume as it rises, where fluid maintains its volume. Perhaps some strategically located drains as the flame rises (falls)?

@Orinoco: you hit the nail on the head. My thoughts exactly. It’s either that or duplivert’ed metaballs that have a diminishing scale IPO. I don’t think that would work out so well though. I’ll work on it today and we’ll see what happens! :smiley:

RobertT made a fire shader for this:

http://blenderartists.org/forum/showthread.php?t=68876&highlight=golden+calf

Check on page 2 for a blend file he released, it might be useful for the effect if not the simulation.

Thanks TheAnimal for that link. I’m going to look at it in a second.
For all interested, here’s what I have so far, and then I’ll post a second image after I’ve looked over RobertT’s methods.

Here’s an image of where I’m at. I’m trying to get back to where I left off before the crash, but I’ve also been toying around with other things so progress is about the same speed. I want to make sure that it can all be animated (which screws up other things). Lastly, I’m still not getting vector blur out. I know that if I could get my first successful look back and vector blur applied then it would be a really nice animated fire… I may have to start a new file to figure out why that happened.
http://www.rgbk.org/zombieking/fire_wip3.jpg

Looks over RobertT’s stuff
Ooh. Distorted Noise as apposed to Cloud is an interesting touch. Also, scaling the texture along the Z axis to half gives it a nice vertical stretch. I’m sure that number may shrink once the motion blur comes back in to play. Thankyou again for the link! Here’s what it’s looking like right now…

color & transparency still attached to “orco” coordinates. This particular frame is beautiful, I’m not going to even be modest about it. The only problem is that it wouldn’t animate well at all because the transparency would just sit there.
http://www.rgbk.org/zombieking/fire_wip4a.png

Here’s the same stuff mapped to an empty object (which makes the scale go wacky). I’ll be tweaking this stuff more in hopes that it looks a lot like the image above and believable when in motion.
http://www.rgbk.org/zombieking/fire_wip4b.png

O_O !! BRAIN STORM! (and note to self!) Try out using material nodes to adapt Majqa’s fire technique into 3D space as the transparency map in order to take care of some diminishing factors. (overlay blend an empty-bound ‘cloud’ with a static gradiation)

Is anyone here an expert with fresnel falloff and transmissivity? Those are my weakpoints here. I found an xray thread a little while back that gave me all the answers, but i can’t find it anymore.

It looks like a fluid simulation upside down.

Right… How about this then?
http://www.rgbk.org/zombieking/youtube1.jpg

Wow, thats impressive.

Wow! Really great job. That video is a massive improvement. Let’s see where you take it from here :slight_smile:

Hello you promice a tutorial I still waiting for !!! Don’t forget us the newbees !!!

What are you using to make the fire? If you used billboards for instance wouldn’t that allow it to be detected by ray tracing?

wow thats awesome fire…I hadn’t thought of using the fluid sim before but it works a treat. Keep it up, cant wait for the tut :slight_smile:

btw I’m in the process of making a flamethrower so this should help loads :slight_smile:

nice update looks sick!

Hey bmud. This might highly peak your interests if you haven’t seen it yet.

http://blenderart.org/issue/2007/03/issue-9.html

I know it’s all about space stuff the first tutorial has the whole heated air effect that you could pry harness and use it with your fire.

Best freaking fire ever! I really want to know how you made that :DDDDDDD

Great animation but still look glassy to me.
It is a difficult task because there are many kinds of fire.
I think, that for experienced Blenderers, realistic fire is possible in Blender.
Just needs lots of observations and good scientific backgroud.
Here is a link to some amaising fire simulations

Here is a paper on simulating fire - found by Google
http://www.graphicsinterface.org/cgi-bin/DownloadPaper?name=2001/129/paper129.pdf

Thanks for this link. It’s constructive crits like yours that are the most helpful. I have something interesting in mind for the distortions… Just give me some more time to figure out the transparency and radiosity problems first. I’ll give you a hint… “toon motion blur”

That’s because… it is… hence why I asked if anyone could assist me in making an “xray” or “water colour” kind of material. with the transmissivity settings. I’ve forgotten completely how to do so, and randomly moving the sliders around doesn’t ever get me anywhere.

I think the real issue is that a “halo” material doesn’t use texture mapping coordinates per-point. Billboards are particles only, and I’m not using particles at all. As for your other question: The answer is complicated and incomplete. Read the first post, sillypants.

@ lokidg: What’s your native language, buddy? When I publish the tutorial, I’ll be happy to include a subtitle file (in english), and perhaps you’d like to help it be translated for other people.