> That looks good, i wonder if some reflection would be good, of course that
> would require some environment to reflect.
>

I'll make tests at home...

>
> I had a look at the shader code and although i do not yet completely
> understand how it works, the same should be possible with the slope
> pattern, although you then have to take the light positions into account.
>

I don't comment my tests in general...I know, it's not a good thing...
The advantage of the shader is that the lights positions are given (not
exactly but, the result is the same, you know where it comes from) and ease a
lot the work...this shader is simple (I think) because, there is no real
physic behind !
I just do a gradient with the 2 colors. the coef is given by the angle between
the light and the surface normal (Ln.Nn).

            David

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>
> I'll make tests at home...
>

I made tests at home !!

               David

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Attachments:
Download 'antiblobs rad.jpg' (31 KB)

Preview of image 'antiblobs rad.jpg'

It looks good, some aspects of iridescence are still missing, but it's
probably difficult to simulate with povray anyway.  

I found that combining radiosity with shaders somehow leads to strange
results, in this case radiosity should not have much influence on the
object, but i did not manage to achieve that.  

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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gemelli david wrote:
> 
> > Might want to try something like in:
> >
> > Message-ID: <39A31644.AB3DE5EF@online.no>
> > Date: Wed, 23 Aug 2000 02:09:40 +0200
> > From: Tor Olav Kristensen <tto### [at] onlineno>
> > Subject: 72 Antiblobs (120kB + 22kB)
> 
> Don't know if you wanted ME to do it but, here it is !
> (thanks Tor for the scene... and Christoph for the idea...)

I'm happy to see this !

But can you please explain to me what a "shader" is ?

And what is POVMan ?


-- 
Best regards,

Tor Olav

mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Tor Olav Kristensen wrote:

> But can you please explain to me what a "shader" is ?
>
> And what is POVMan ?

POVMan is a POV/Renderman hybrod or such IIRC.

I'm going to venture a guess on shaders, but I don't actually know: does
it let you specify a falloff_map of sorts, like a color_map or slope_map
except related to brilliance and angle of incidence? I'm guessing
because I notice hue changes perpendicular to the light direction in
these renders.

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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In article <3A663311.4A4A8FE1@faricy.net>, David Fontaine 
<dav### [at] faricynet> wrote:

> POVMan is a POV/Renderman hybrod or such IIRC.

It is an unofficial version of POV-Ray which supports RenderMan-like 
shaders.


> I'm going to venture a guess on shaders, but I don't actually know: does
> it let you specify a falloff_map of sorts, like a color_map or slope_map
> except related to brilliance and angle of incidence? I'm guessing
> because I notice hue changes perpendicular to the light direction in
> these renders.

Shaders are just bits of code that specify how the color of the surface 
is calculated. POVMan shaders are written in a special language that is 
different than POV-Script and based on the RenderMan lanugage, it is 
basically a way to customize rendering without having to patch the 
program. The shaders are interpreted, so there is a speed penalty for 
this flexibility. And I think POVMan shaders are just special pigments, 
so you should be able to combine them with ordinary finish and normal 
features, but would normally use ambient 1 to get the unmodified result 
of the shader.
Basically super-functions which can handle colors and vectors and have a 
different set of built-in functions, and result in a color instead of an 
index for a color_map.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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Chris Huff wrote:

> > I'm going to venture a guess on shaders, but I don't actually know: does
> > it let you specify a falloff_map of sorts, like a color_map or slope_map
> > except related to brilliance and angle of incidence? I'm guessing
> > because I notice hue changes perpendicular to the light direction in
> > these renders.
>
> Shaders are just bits of code that specify how the color of the surface
> is calculated. POVMan shaders are written in a special language that is
> different than POV-Script and based on the RenderMan lanugage, it is
> basically a way to customize rendering without having to patch the
> program. The shaders are interpreted, so there is a speed penalty for
> this flexibility. And I think POVMan shaders are just special pigments,
> so you should be able to combine them with ordinary finish and normal
> features, but would normally use ambient 1 to get the unmodified result
> of the shader.
> Basically super-functions which can handle colors and vectors and have a
> different set of built-in functions, and result in a color instead of an
> index for a color_map.

So in a way I was right... :)

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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In article <3A6667DC.D7C2FF34@faricy.net>, David Fontaine 
<dav### [at] faricynet> wrote:

> So in a way I was right... :)

Sort of...there is no "falloff_map" and it doesn't use a color_map, but 
it lets you do all those things. (As well as nearly any other effect 
that can be programmed.)

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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Chris Huff wrote:

> > So in a way I was right... :)
>
> Sort of...there is no "falloff_map" and it doesn't use a color_map, but
> it lets you do all those things. (As well as nearly any other effect
> that can be programmed.)

I did make it a simile. :P

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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In article <3A68CD06.44366D19@faricy.net>, David Fontaine 
<dav### [at] faricynet> wrote:

> I did make it a simile. :P

Well, I *did* fail the second half of Grammar III last year... ;-)

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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