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 shweta06-30-2005, 04:56 PMHi I am looking for an algorithm to get the mushroom shape as you get when a nuclear explosion happens .Right now I have aprogram which has circle algorithm .concentric circles created.I wanted to have a curve to represent the mushroom shape.My aim is to get realistic nuclear explosion . Any help or links would be welcomed. Thanks Shweta
pekko
06-30-2005, 07:39 PM
try this paper:

http://graphics.stanford.edu/~fedkiw/papers/stanford2003-02.pdf (http://graphics.stanford.edu/%7Efedkiw/papers/stanford2003-02.pdf)

ILM used these techniques in terminator 3

I have been trying to implement this method and i am quite far. The biggest problem so far has been the multiple scattering inside volume. But i think i have fast solution for this, but i have not seen it in action :( ... maybe in couple of months

Fluid mathematics has been too difficult for me. Jos Stam has published his game fluid engine which should do the trick.

operativem
07-01-2005, 02:14 AM
I'm not sure what level of realism you need, but you might want to read about particle systems, if you haven't already. I would use a particle system to simulate a mushroom cloud, and although the physics of a mushroom cloud/fireball are complex, a decent approximation is doable. I think [speculation here] mushroom clouds are formed by rapidly expanding gases and updrafts created from the heat of the explosion. You might even call a fire station, as those guys know a lot about fire and explosions. This month's Wired magazine has an interesting article about firefighters and their extensive knowledge on the topic of fire/explosions/etc.

shweta
07-01-2005, 01:26 PM
Thanks for the help. will try your suggestion and will let you know.I was try to get some code from software hotspot which does fire nuclear explosion simulation.any idea about it?
I am using particle system for my work.
Thanks
shweta

operativem
07-01-2005, 06:31 PM
I am unfamiliar with the code at hotspot. If you don't already have a copy, you should buy the book "Computer Graphics, Principles & Practice". I think it has some information on this topic.

shweta
07-11-2005, 02:41 PM
Hi guys,
I did get the mushroom shape.
I did the following:
1.created my particle system which had constant radius and increaseing height.(created concentric circles too).with little gravity,so the system shoots up.
2.Second particle system with gravity and varying radius the curve was formed ,A sine wave path was given to the radius which showed some randomness.
Is this they way(correct and only way)?I am using openscenegraph .But for the fire ,it appears dull to me (the fire class in osg).How do I get the illuminace/glow/flash of lght which last?
Thanks for the help.
Shweta

finalight
08-07-2005, 09:11 AM
We created these using the other method. No math - just try to make it look right: http://finalight.com (http://finalight.com/) Just a thought.

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