referring to the discussion in povray.newusers, i tried to make a pattern
testing if there is something 'above' the evaluated point.

syntax right now is:

pigment {
  project <vector>, object
  [color 1]
  [color 2]
}

I called it 'project', because it's like something being projected on the
object.  Together with megapov's slope pattern it could do what Marc
wanted.

Comments and suggestions welcome of course.

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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Attachments:
Download 'project1.jpg' (10 KB)

Preview of image 'project1.jpg'

I don't get it. Please post a simpler example... perhaps on a cylinder or a
sphere alone on a plane.

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WOW! That was really fast!

I think that will help a lot. 'object' is the object against which the
pattern test?

Shouldn't the foreground side of the bottom box and the sides of the
floating box be all red? Or was your "projection-vector" not straight
<0,1,0>?

Now were can I get it? ;-)

Thanks a lot,

Marc-Hendrik

Christoph Hormann schrieb in Nachricht <3A60C06B.2591866A@gmx.de>...
>
>referring to the discussion in povray.newusers, i tried to make a pattern
>testing if there is something 'above' the evaluated point.
>
>syntax right now is:
>
>pigment {
>  project <vector>, object
>  [color 1]
>  [color 2]
>}
>
>I called it 'project', because it's like something being projected on the
>object.  Together with megapov's slope pattern it could do what Marc
>wanted.
>
>Comments and suggestions welcome of course.
>
>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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Marc-Hendrik Bremer wrote:
> 
> WOW! That was really fast!
> 
> I think that will help a lot. 'object' is the object against which the
> pattern test?

Yes.

> 
> Shouldn't the foreground side of the bottom box and the sides of the
> floating box be all red? Or was your "projection-vector" not straight
> <0,1,0>?

If the projection vector and the surface are parallel, things do not work
very good, so it gets spotted.  Just like doing 'trace()' right across the
side of a box.  

> 
> Now were can I get it? ;-)
> 

Well, i did not yet test it very detailed, maybe also want to change some
things again, so i don't want to publish it right now.  If you like to use
it for a certain project, i can send you a copy via pm.

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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"Tony[B]" wrote:
> 
> I don't get it. Please post a simpler example... perhaps on a cylinder or a
> sphere alone on a plane.

That would not be very meaningful, just their 'shadows' on the plane and
different colors for upper/lower side of the objects.  

Just imagine where the objects get white when it snows...

Or in other words: Viewed from above with orthographic camera, everything
is blue, the whole rest is red.

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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Christoph Hormann wrote:

> Or in other words: Viewed from above with orthographic camera, everything
> is blue, the whole rest is red.

Ah, now I get it. I wasn't sure what it did either.

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

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In article <3A60C06B.2591866A@gmx.de>, Christoph Hormann 
<chr### [at] gmxde> wrote:

> referring to the discussion in povray.newusers, i tried to make a pattern
> testing if there is something 'above' the evaluated point.

This looks very similar to a simple version of a "visibility" pattern I 
was working on once. I used multiple samples to allow a blurred result, 
and my pattern was mainly to be used for a curvature pattern to make 
things like "patina" in concave areas on a copper sculpture.
The proximity pattern could probably be used for this too, using the 
sample_weighting feature (though I'm not sure that made it into 
MegaPOV). Both of these would be very slow, though.

The "project" keyword doesn't seem very intuitive, though...maybe it 
should be added to the "object" pattern instead. Or "visibility". :-)

-- 
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:
> 
> This looks very similar to a simple version of a "visibility" pattern I
> was working on once. I used multiple samples to allow a blurred result,
> and my pattern was mainly to be used for a curvature pattern to make
> things like "patina" in concave areas on a copper sculpture.
> The proximity pattern could probably be used for this too, using the
> sample_weighting feature (though I'm not sure that made it into
> MegaPOV). Both of these would be very slow, though.

I also thought of using several samples, but it was a bit comlicated for
me right now :-)
 
> The "project" keyword doesn't seem very intuitive, though...maybe it
> should be added to the "object" pattern instead. Or "visibility". :-)
> 

Sounds like a good idea, although i also thought of making the value
proportional to the distance of the 'ceiling'.

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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