Blinn is a type of shading like phong that is good for simulating cloth
materials (I saw it in Max). Subsurface scattering is a rendering concept
that considers all objects partially transparent and renders the light and
its interactions just a little below the surface. If also seems to help in
wetting or dampening surfaces.

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These sound interesting, know of any web sites with more info?

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About blinn shading, no, not really. Perhaps somewhere on Kinetix's site, or
you can look around. About the subsurf scat, someone recently posted a link
to the original inspiration to Nathan Kopp's photon mapping and it's in
there.

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There seems to be a problem with filtering objects, filter is treated
like transmit. I haven't downloaded the bug-fixed version yet, but this
seems to be unrelated to that bug.
For example, this:
sphere {< 0, 0, 0>, 1
  pigment {color Green filter 1}
 translate < 0, 1.0001, 0>
}
is invisible when placed on a ground plane, when it should show up as a
green transparent sphere.
This happens with #version 3.1 but not with #version 3.14159, I don't
know if it happens in UVPov.

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Chris Huff wrote:
> 
> There seems to be a problem with filtering objects, filter is treated
> like transmit. I haven't downloaded the bug-fixed version yet, but this
> seems to be unrelated to that bug.
> For example, this:
> sphere {< 0, 0, 0>, 1
>   pigment {color Green filter 1}
>  translate < 0, 1.0001, 0>
> }
> is invisible when placed on a ground plane, when it should show up as a
> green transparent sphere.
> This happens with #version 3.1 but not with #version 3.14159, I don't
> know if it happens in UVPov.

I recall that Warp mentioned something about a dissapearing filtered sphere
problem with UVPov v6.0 that Nathan was going to fix for UVPov v6.1. That
may explain the difference.

-- 
Ken Tyler -  1200+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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Oh, and the sphere_sweep template form produces b-spline_sphere_sweep
instead of b_spline_sphere_sweep, I thought this was fixed before?

Still using the Nov 15 version, I lost the connection in the middle of
downloading the new version. :-(

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Chris Huff <Chr### [at] compuservecom> wrote:

> Oh, and the sphere_sweep template form produces b-spline_sphere_sweep
> instead of b_spline_sphere_sweep, I thought this was fixed before?
We almost had a hardattack while reading this mail! :-)
Keeping cool was the way to go... yes, it was fixed and still is but
there were two spots in the source producing this text. We cleaned up
the sources and guess what: we kept the code producing the wrong test.
It is harmless, and we will fix it for a next version.
Thanks for taking a few year of of our lives. :-) :-)

> Still using the Nov 15 version, I lost the connection in the middle of
> downloading the new version. :-(
We know that feeling, we had the same problem if we wanted to download
from the US. We must admid that this didn't happen for a long time now.
We do know that we have a good server, located here in Belgium, and
perhaps you have to solve it like we did: download after rush hours.

Smellenbergh

-- 
e-mail:sme### [at] skynetbe

http://users.skynet.be/smellenbergh

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Chris Huff <Chr### [at] compuservecom> wrote:

> There seems to be a problem with filtering objects, filter is treated
> like transmit. I haven't downloaded the bug-fixed version yet, but this
> seems to be unrelated to that bug.
> For example, this:
> sphere {< 0, 0, 0>, 1
>   pigment {color Green filter 1}
>  translate < 0, 1.0001, 0>
> }
> is invisible when placed on a ground plane, when it should show up as a
> green transparent sphere.
> This happens with #version 3.1 but not with #version 3.14159, I don't
> know if it happens in UVPov.

We tried it and we always get a correct image. The whole scene file we
used is included in this mail.
 
A little note:
if you set the version in the source, the setting in the prefs dialog
will be overwritten. Thaugt we could better tell you, we have been
looking for a bug that wasn't there. ;-)

There was a problem but that has been fixed by Nathan in 6.1, we waited
for v6.1 to release our version. 
Are you sure you weren't working with a version you compiled yourself?

If you can reproduce it again with the nov 17 version, please e-mail us
the complete source and a prefs file. 

A little advice: if you have questions about any patch we included,
please post your message in a group where you are more likely to get an
answer (patches, general,..) and give it an appropriate 'Subject'.

Smellenbergh

// Persistence of Vision Ray Tracer Scene Description File
// File: ?.pov
// Vers: 3.1
// Desc: Checkered Floor Example
// Date: mm/dd/yy
// Auth: ?
//

#include "colors.inc"
//#version 3.1;

global_settings
{
  assumed_gamma 1.0
}

// ----------------------------------------
camera {
    perspective 
    location <0.0, 1.5, -5>
    up y*image_height right x*image_width
    angle 60
    look_at <0.0, 0.0, 0.0>
}


sky_sphere
{
  pigment
  {
    gradient y
    color_map { [0.0 color blue 0.6] [1.0 color rgb 1] }
  }
}

light_source
{
  0*x // light's position (translated below)
  color red 1.0  green 1.0  blue 1.0  // light's color
  translate <-30, 30, -30>
}
sphere {< 0, 0, 0>, 1
  pigment {color Green filter 1}
 translate < 0, 1.0001, 0>
}

// ----------------------------------------
plane
{
  y, -1
pigment {
    checker 
    rgbft <1.0, 1.0, 1.0, 0.0, 0.0>,
    rgbft <0.6, 0.6, 0.6, 0.0, 0.0>
}

}



-- 
e-mail:sme### [at] skynetbe

http://users.skynet.be/smellenbergh

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>A little advice: if you have questions about any patch we included,
please post your message in a group where you are more likely to get an
answer (patches, general,..) and give it an appropriate 'Subject'.<

Ok, discussion continued under povray.unofficial.patches, in a message
titled "Unofficial MultiPatch filter bug?".

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For subsurf scat check out:

http://graphics.stanford.EDU/~henrik/

for a first start point....

hope, this is useful...

v
Zan

TonyB wrote:

> About blinn shading, no, not really. Perhaps somewhere on Kinetix's site, or
> you can look around. About the subsurf scat, someone recently posted a link
> to the original inspiration to Nathan Kopp's photon mapping and it's in
> there.

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