Hello all. I found this great (or so I think) page that explains how to
model all kinds of real world events; string, cloth, gel, spherical
heighfields, fire, water, wu particles, etc. etc. I wanted to translate
the pseudo code to POV, but I found myself unable to do so. I kinda
wanted to surprise everybody with, I dunno, maybe a macro or something
for cloth and string at least. I am submitting the link for all those
advanced enough to actually make something out of this, unlike me.
Enjoy. =)

        http://freespace.virgin.net/hugo.elias/

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Anthony Bennett wrote: <36D1DB4A.C76B99E1@panama.phoenix.net>...
>Hello all. I found this great (or so I think) page that explains how to
>model all kinds of real world events; string, cloth, gel, spherical
>heighfields, fire, water, wu particles, etc. etc. I wanted to translate
>the pseudo code to POV, but I found myself unable to do so. I kinda
>wanted to surprise everybody with, I dunno, maybe a macro or something
>for cloth and string at least. I am submitting the link for all those
>advanced enough to actually make something out of this, unlike me.
>Enjoy. =)
>
>        http://freespace.virgin.net/hugo.elias/


Yeah, the page is pretty cool, but I only think so because I'm a coder. Not
much of the things there can be done in povray, most of it are for real-time
applications. The pages about cloth and that stuff is not about the actual
texture. it's more about how cloth and other soft objects folds and moves.
I will how ever try to do a povray macro for producing the spherical
heightmaps. Shouldn't be too hard.

/Anders

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Anders Haglund <95a### [at] ostrabouddevallase> wrote:

  >>        http://freespace.virgin.net/hugo.elias/
  > Yeah, the page is pretty cool, but I only think so because I'm a coder.
  > Not much of the things there can be done in povray, most of it are for
  > real-time applications.

?.. that should make it easier to implement, not somehow impossible or
inappropriate, as you suggest. just crank out the data to a bunch of .pov's,
one for each frame.

  > The pages about cloth and that stuff is not about the actual texture.

no, why would you want it to be? the texture of a cloth is wholly
uninteresting, it's the shape that's the interesting bit. after that you can
slap on any texture you want.

  > it's more about how cloth and other soft objects folds and moves.

yes. implement it and have it put out meshes of smooth triangles.

I've implemented it, but I never got it stable, and it just seemed to
hackish to put too much time in tweaking it. too much magic values left and
right. I have finished some flag animations, but they all look rubbery and
the numerical instability always botches things up in the end (ironically
always when the flag is just settling).

the method as described in the siggraph98 paper "Large Steps in Cloth
Simulation" by Baraff and Witkin (it's online someplace if you're interested,
altavista for it), which claims to solve exactly the problems the above
method has, seems much less of a hack, but I haven't gotten around to
implementing that, and it's not in as easily digestable chunks as the page
mentioned above is.

the point being that such things can very well be used in conjuction with
povray. just output .pov's and let the program work.

now I just need to find out how to render a volume density field with povray.

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