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seb4d
03-15-2003, 10:08 AM
Hi everyone !
For my school project I'm looking for a way to create a realistic forest fire.
We filmed a real forest and I wonder now how we can achieve realistic looking fire.

The programs we have are Maya, 3DSMax, After Effects, Photoshop and Digital Fusion.
Can someone tell me what I can do with that ?

Thanks.

Tommi
03-15-2003, 11:30 AM
First of all, I'm no expert and haven't done something like that, yet, but I can imagine, that this task depends on what kind of video footages you have. Are these shots done within the forest or above/from distance? Closeups on trees might lead to troubles, because these trees don't look burnt and it would look odd if you just put a fire layer above a healthy tree. Maybe some distance shots with some image manipulations (darken the trees to make look them burnt) could lead to the right direction.
For the realistic fire you could use stock footages of real fire or maybe make your own shots of fire, key it out and so on....

seb4d
03-15-2003, 06:12 PM
ok, I've made some tests with Digital Fusion.
Here is a short example, tell me what you think of it.
http://membres.lycos.fr/seb4d/feu_test.avi

Tommi
03-15-2003, 06:53 PM
That looks great so far!
But honestly not so realistic due to two reasons which currently come to my mind. First of all, the fire does not interact with the surroundings. I know, that must be something hard to gain and honestly I have no clue, but by the fire itself, the ground and also the background should flicker in the color tone of the fire. You could add some CG trees and also some CG leaves which are glowing and are black.
Second of all, the fire is too orange. It need to be more yellowish-brownish. I like the smoke. Maybe you could add more smoke, mix the fire with it. Burning plants and wood cause a lot of smoke and damp due to the water that evaporates.
Just a few ideas :shrug:

seb4d
03-15-2003, 07:12 PM
it's just a few ideas but they're very good, I didn't thought of all these details !
I agree with you that the color is too saturated in organge tones, I will darken it and add some more details.
As for the interaction with the scene there is none for the moment. I have just worked on the fire itself.
Thanks again for your advice !

Bye

Tommi
03-15-2003, 07:17 PM
Lookin forward to some updates!
By the way - you may want to post this to the WIP thread. You'll get loads of response and good advice!

Good Luck! :wavey:

Hugh
03-16-2003, 02:11 AM
Also, it was very obvious that the vortices were static - maybe move them through the fire during it....

daysleeper
03-16-2003, 04:09 AM
may be u need a little bit of haze ...
and the groun under the fire must be more dark
and the fire must throw some sort of a shadow over the background ...
i think u have to put something in the fire ... branches or something like that ...

i think thats enough ... for now :]


sorry for my english ;]

seb4d
03-16-2003, 11:09 AM
I agree for the vortices, they're static I'll try to animate them. The problem is that the vortex is deforms the render node of the particles so that I get stretched flames like in real fire. If I place a vortex field directly to the particles node they behave the same way but there is no stretching cause each particle is still a bunch of points. I would need particle motion blur but I think it's not possible in Digital Fusion.

I'll add some details too as you said daysleeper.

thx guys !

jussing
03-17-2003, 04:24 PM
Hi!

That fire looks much better than I'd expected!

Here's my advice on how to improve it:

Make 3 layers of fire: far, medium, and close (where "close" is the one you've already got.

Then mask out the trees for the respective layers, and insert the fire, so it looks like it's behind those trees. (After Effects will be good for this)

That way I think you can achieve a better look of how the whole forest is on fire, and not just a blob of kerosene in front of the closest trees.

Little thoughts:
- If you render as much as three layers of fire, you'll propably have to somehow give the fire less density, or you won't be able to see the forest anyway.
- When masking out trees, plan your shots so the camera doesn't move! :) ...or you'll be in for the nightmare of your life...
- When animating the vortexes, maybe you should animate them moving from down and up... I've never tried anything like this, buit my best guess is it'll look weird if they just move around from side to side...

Good luck! I'm looking very much forward to your next update!

Regards,
- jonas

Jayk2k
03-17-2003, 05:33 PM
Seb4d;

Great work on those flames. You can apply motion blur to the particle system under the radio-active tab in the Prender tool, and adjust the settings as needed. Be warned though, this will slow things down a bit to a lot depending on your settings.

Once you have a bit more work on this completed, We'd like to offer you a spot on our "Go with the Flow" area of our website provided it meets qualifications.

Best of luck with your project...

seb4d
03-18-2003, 07:57 AM
first of all i'd like to thanks again everybody for your tips and encouragement (it sounds like award ceremony but i really mean it ;P).
I will follow your advice Jussing, it seems a great idea to make 3 layers, it will give more depth to the fire.

Jayk2k thanks for motion blur, I didn't know where this option was and it will be helpfull, and i'm not afraid of rendering time.
As for your offer of a spot i'm very glad to accept, thank you very much. For the moment I'm working on my 3d character animation, the fire is still some early tests I do for the next weeks when it's time for me to integrate it in my video. As soon as I improve the fire I post another picture here in CGTalk, I think its a matter of days or week.

Thanks all !

3DDave
03-20-2003, 11:12 PM
Particel motion blur and z-depth are no problem for DF.

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