"Jan Walzer" <nos### [at] informatikuni-hallede> writes:

> > I'm currently working more or less (read: less) on an implementation
> > of the fur that is presented in this paper. A short film of a furry
> > torus can be seen at http://www.povray.willhalm.de/tracegallery/ .
> maybe there's something wrong with your link ???

I don't know. I tested it and it worked - and still works - fine for me.
There seems to be something wrong with the forwarding. So, try
http://www.fmi.uni-konstanz.de/~willhalm/graphics/tracegallery/
instead.

Thomas

-- 
http://thomas.willhalm.de/ (includes pgp key)

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"Jan Walzer" <nos### [at] informatikuni-hallede> writes:

> > > Can't we use it as a kind of Media ???
> >
> > You're not the first one to come up with this idea. It has already be
> > phrased by Kajiya and Kay in "Rendering Fur with Three Dimensional
> > Textures", Computer Graphics, Volume 23, Number 3, July 1989.
> Where to get this paper ?

First try the library of the university in Halle. If it's not available
there, you can get it using <insert what "Fernleihe" means in English>.
Alternatively, it may be downloadable with a credit card at www.acm.org,
because it's in a magazine that is published by the ACM (which I forgot to
mention). 
 
> [...]
> > In my opinion, this approach has a lot of potential. Apart from fur,
> > I think that grass and forests can be renderered this way. Of course,
> > someone must first find an adequate lighting model for these objects.
> > However, you should be aware that this method will only work for
> > distant views.
> hmmm ... but am I right, about the rendertime ...
> I've thougt about the last night, and found that therefore the "steps in the
> media" (or how was it called) have to be massivly increased, to get all the
> branches of a high-detailed tree, don't they?
> The standard for this is AFAIK 10 steps, and how can this make a good tree ?

I cannot speak for trees but for fur. Using media makes mainly sense, when
you don't care about details. Instead of a higly detailed image, you want
to look your fur (tree, grass, forest) good from a distance. So, you 
approximate the reflections instead of generating a lot of cylinders.

As far as I know, the number of steps is also calculated adaptively.
That's why I suspect the number of steps to be higher by default in
such applications. However, I didn't care about them too much so far.
I have tried the new sampling methods in the megapatch. They didn't
work very well in case of my furry torus.

Thomas

-- 
http://thomas.willhalm.de/ (includes pgp key)

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Chris Huff <chr### [at] yahoocom> writes:

> In article <387ba7f6@news.povray.org>, "Jan Walzer" 
> <nos### [at] informatikuni-hallede> wrote:
> 
> > hmmm ... but am I right, about the rendertime ...
> > I've thougt about the last night, and found that therefore the "steps in 
> > the
> > media" (or how was it called) have to be massivly increased, to get all 
> > the
> > branches of a high-detailed tree, don't they?
> > The standard for this is AFAIK 10 steps, and how can this make a good 
> > tree ?
> 
> I really think the best use of a density pattern to make a tree or grass 
> would be in an isosurface, which is actually slightly similar to media 
> in some ways. And their render speed is usually quite tolerable, 
> although complex ones with a lot of very small details can be slow.

I have tried to model the fur with an isosurface and failed miserably.
I don't know why this didn't work. With media however, it turned out
quite weill. For this reason, I believe that it may be worth the effort 
to try grass or needles with media.

Thomas

-- 
http://thomas.willhalm.de/ (includes pgp key)

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> > > The standard for this is AFAIK 10 steps, and how can this make a good
> > > tree ?
> >
> > I really think the best use of a density pattern to make a tree or grass
> > would be in an isosurface, which is actually slightly similar to media
> > in some ways. And their render speed is usually quite tolerable,
> > although complex ones with a lot of very small details can be slow.
>
> I have tried to model the fur with an isosurface and failed miserably.
> I don't know why this didn't work. With media however, it turned out
> quite weill. For this reason, I believe that it may be worth the effort
> to try grass or needles with media.
... and again this Object: "isosurface"
I've read a lot of this here in group, but I never heard something of this
before ...
Is it an extension of POV or have I to read for it in the standard POV-Docu?
Is it provided by any graphical frontend? I only seldom use Handcoding
...(yes, I use Moray)

But: What is an "isosurface" ? ...

PS: Don't answer if it is an RTFM-question ...

Jan

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Jan Walzer wrote:

> ... and again this Object: "isosurface"
> I've read a lot of this here in group, but I never heard something of this
> before ...
> Is it an extension of POV or have I to read for it in the standard POV-Docu?
> Is it provided by any graphical frontend? I only seldom use Handcoding
> ...(yes, I use Moray)
> 
> But: What is an "isosurface" ? ...
> 
> PS: Don't answer if it is an RTFM-question ...
> 
> Jan

An isosurface is a mathematical surface representation that conforms to a
set of predefined rules. Isosurfaces are not currently available in the
official version of POV-Ray. Isosurfaces are currently only available in
unofficial versions of the program but will most likely be included in
the next official release POV-Ray.

You can visit the original home page of the isosurface for specifics on
the subject -

http://www.public.usit.net/rsuzuki/e/povray/iso/index.html


And if you want to try using them in your work now there are currently
four platforms that you can find an updated patch that has Isosurfaces
available -

For the Windows OS -
http://nathan.kopp.com/patched.htm

For the Dos OS
http://www.sgib.co.uk/

For the Unix/Linux OS
http://www.mailbag.com/users/mtgordon/megapov.html

For the Mac OS
http://users.skynet.be/smellenbergh/main.html

-- 
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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