What I had in mind was more along the lines of having the translucency
{...} stuff be in the interior {...} portion, and have a
double_illuminate keyword in the finish {...} statement.
Double-illuminate would affect the surface of the object (both inside
and outside would be illuminated), and translucence would depend on
thickness, and affect light passing through(photon-mapping + blurred
reflections + translucence = WOW!). I know that translucence can be done
with media, but this is hard to control and slow. A special keyword with
a sampling method designed for doing translucence would be much better.

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I'm hesitant to mention this because, for all I know, it's in there
somewhere and I haven't found it yet:

texture coordinates for triangle meshes.

VRML has got this, and it's marvelous.  Quite often I'll sketch in
VRML to get the basic geometry and camera and lighting and then
export to POVRay, and it's kind of weird to lose capabilities
when I go up to POVRay.
+-------------------------------+--------------------------------------+
| Rev. Bob "Bob" Crispen        |            "IT FOUND ME!"            |
| cri### [at] hiwaaynet            |      Campus Crusade for Cthulhu      |
+-------------------------------+--------------------------------------+

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Have you looked at the tri-color macro for triangles yet? You may have and
I'm leading you to old stuff. Anyway, it's at:

http://www.geocities.com/SiliconValley/Lakes/1434/otherincludes.html

No idea if this is the same kind of thing you are looking for or not, but
it does apply a pigment to points on the triangles.


Bob Crispen wrote:
> 
> I'm hesitant to mention this because, for all I know, it's in there
> somewhere and I haven't found it yet:
> 
> texture coordinates for triangle meshes.
> 
> VRML has got this, and it's marvelous.  Quite often I'll sketch in
> VRML to get the basic geometry and camera and lighting and then
> export to POVRay, and it's kind of weird to lose capabilities
> when I go up to POVRay.
> +-------------------------------+--------------------------------------+
> | Rev. Bob "Bob" Crispen        |            "IT FOUND ME!"            |
> | cri### [at] hiwaaynet            |      Campus Crusade for Cthulhu      |
> +-------------------------------+--------------------------------------+

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto://inversez@aol.com?Subject=PoV-News

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Bob Hughes wrote:

> Have you looked at the tri-color macro for triangles yet? You may have and
> I'm leading you to old stuff. Anyway, it's at:
> 
> http://www.geocities.com/SiliconValley/Lakes/1434/otherincludes.html
> 
> No idea if this is the same kind of thing you are looking for or not, but
> it does apply a pigment to points on the triangles.

Many thanks, Bob.  That's a feature request I didn't mention, but
which has a very high coolness-per-byte payoff: per-vertex coloring.
I'm off to try it now.

What I had in mind was mapping 2D coordinates of a texture image to
points on a mesh.  The way it's done in VRML is explained at
http://home.hiwaay.net/~crispen/vrmlworks/tutorials/texture.html
There's a fairly spectacular example of texture coordinates at
http://home.hiwaay.net/~crispen/worlds/avatar/bobhead.wrl -- a
friend of mine did this for me last summer at SIGGRAPH.  It's three
photos overlaid on three laser rangefinder scans of my head.

They messed up on my nose -- it doesn't point west quite so much
as it does in one of those meshes, but thanks to texture coordinates,
when I move the points of my nose over, the texture will move with
the points.

Granted that file formats where meshes are central and you have
point sets and indices (Inventor, VRML, lots of others) make the
texture coordinate mapping pretty compact, but compactness doesn't
matter so much in POV.  There's no reason why it couldn't be
applied to the POV notation just like Chris's tri-colour macro.
Instead of rgb value, just specify the texture image for the
triangle and the coordinates within the image for each point.
+-------------------------------+--------------------------------------+
| Rev. Bob "Bob" Crispen        |            "IT FOUND ME!"            |
| cri### [at] hiwaaynet            |      Campus Crusade for Cthulhu      |
+-------------------------------+--------------------------------------+

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That head mesh is great. Only other one I've seen was on TV. I'd wager it
was the crowd at SIGGRAPH that caused the nose to be off center. Somebody
probably nudged the tripod (if the laser range finders were tripod
mounted). heh-heh
From what I could make out of that tri-color macro I thought perhaps a
whole texture (including image_map?) might be done the same way. I'm not
much a user of meshes though.
In case you hadn't heard or seen it, there's a thing called Photo Modellor
that applies images to meshes you create by plotting out the points onto
several views of the pictured object (front, side, top, etc.). Only tough
part is the manual mesh making and I didn't have any success learning to
get the surfaces defined enough. Seems potentially a great thing, free
trial version available. Mike Hough told several of us about it at AOL,
it's at:

 http://www.eossystems.com/Lite/


Bob Crispen wrote:
> 
> Bob Hughes wrote:
> 
> > Have you looked at the tri-color macro for triangles yet? You may have and
> > I'm leading you to old stuff. Anyway, it's at:
> >
> > http://www.geocities.com/SiliconValley/Lakes/1434/otherincludes.html
> >
> > No idea if this is the same kind of thing you are looking for or not, but
> > it does apply a pigment to points on the triangles.
> 
> Many thanks, Bob.  That's a feature request I didn't mention, but
> which has a very high coolness-per-byte payoff: per-vertex coloring.
> I'm off to try it now.
> 
> What I had in mind was mapping 2D coordinates of a texture image to
> points on a mesh.  The way it's done in VRML is explained at
> http://home.hiwaay.net/~crispen/vrmlworks/tutorials/texture.html
> There's a fairly spectacular example of texture coordinates at
> http://home.hiwaay.net/~crispen/worlds/avatar/bobhead.wrl -- a
> friend of mine did this for me last summer at SIGGRAPH.  It's three
> photos overlaid on three laser rangefinder scans of my head.
> 
> They messed up on my nose -- it doesn't point west quite so much
> as it does in one of those meshes, but thanks to texture coordinates,
> when I move the points of my nose over, the texture will move with
> the points.
> 
> Granted that file formats where meshes are central and you have
> point sets and indices (Inventor, VRML, lots of others) make the
> texture coordinate mapping pretty compact, but compactness doesn't
> matter so much in POV.  There's no reason why it couldn't be
> applied to the POV notation just like Chris's tri-colour macro.
> Instead of rgb value, just specify the texture image for the
> triangle and the coordinates within the image for each point.
> +-------------------------------+--------------------------------------+
> | Rev. Bob "Bob" Crispen        |            "IT FOUND ME!"            |
> | cri### [at] hiwaaynet            |      Campus Crusade for Cthulhu      |
> +-------------------------------+--------------------------------------+

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto://inversez@aol.com?Subject=PoV-News

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I just want a function to tell me the height at a particular coordinate of a
heightfield.  That way I can programatically place objects at the surface of
the heightfield instead of having to place objects by hand with
trial-and-error or externally with a program.

Imagine if you will... Romans charging across a "Khaki" rippling HF plain in
close regular but randomized formation.  Or barbarian blue-skinned celts,
wild-eyed and naked skewered on roman philum.

Seriously, a cohort of soldiers flowing across the crest of a heightfield
would be much more impressive and interesting to look at than ranks of them
lined up on level "boxes".

Towns and villages could be contoured to the terrain giving much more
realistic "spaces".

Owwww heck... just getting the trees to set right on the landscape would be
nice.

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On Sun, 30 May 1999 12:25:45 -0500, Bob Crispen wrote:
>I'm hesitant to mention this because, for all I know, it's in there
>somewhere and I haven't found it yet:
>
>texture coordinates for triangle meshes.
>
>VRML has got this, and it's marvelous.  Quite often I'll sketch in
>VRML to get the basic geometry and camera and lighting and then
>export to POVRay, and it's kind of weird to lose capabilities
>when I go up to POVRay.
>+-------------------------------+--------------------------------------+
>| Rev. Bob "Bob" Crispen        |            "IT FOUND ME!"            |
>| cri### [at] hiwaaynet            |      Campus Crusade for Cthulhu      |
>+-------------------------------+--------------------------------------+

Try UVPOV, http://nathan.kopp.com/patched.htm , or the superpatch
(currently offline.)

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On Tue, 1 Jun 1999 09:42:08 -0400, Robert J Becraft wrote:
>I just want a function to tell me the height at a particular coordinate of a
>heightfield.  That way I can programatically place objects at the surface of
>the heightfield instead of having to place objects by hand with
>trial-and-error or externally with a program.

You might look at the trace() function in the superpatch.  It was
designed to do this and more.  Unfortunately, the superpatch is
offline at the moment, but it will go back online within the next
day or so; watch for an announcement.

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Ron Parker wrote:

> Try UVPOV, http://nathan.kopp.com/patched.htm , or the superpatch
> (currently offline.)

Cool.  If the acronym means what I think it does, it's exactly what
I want.

Many thanks.
+-------------------------------+--------------------------------------+
| Rev. Bob "Bob" Crispen        |            "IT FOUND ME!"            |
| cri### [at] hiwaaynet            |      Campus Crusade for Cthulhu      |
+-------------------------------+--------------------------------------+

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Bob Hughes wrote:

> That head mesh is great. Only other one I've seen was on TV.

Thanks -- of course, the only thing I had to do with it apart from
(not) sitting still was to reduce it to something you could download
in your lifetime.  Flamingo Optimizer and Chisel can both decimate
a VRML mesh with texture coordinates without screwing up the
image-to-mesh mapping, which I think is magic.  I can't conceive of
trying to write and debug that code.

> I'd wager it
> was the crowd at SIGGRAPH that caused the nose to be off center. Somebody
> probably nudged the tripod (if the laser range finders were tripod
> mounted). heh-heh

No, it was a problem we both share.  An old friend I hadn't seen in
a while came by and said "Hi, Bob", so naturally I had to take a
drink.  ;-)

The lasers were tripod mounted and they even did an automatic scan
which took about a minute.  He took three scans and three photos
and then imported them into MAX and played with them for about a
minute to join them.  Sorry that I've forgotten who made the
cameras and software, but I'll bet there's a dozen of them at this
year's SIGGRAPH.  Beats the hell out of that little finger thingy
that does sort of reverse STL to scan models in.
+-------------------------------+--------------------------------------+
| Rev. Bob "Bob" Crispen        |            "IT FOUND ME!"            |
| cri### [at] hiwaaynet            |      Campus Crusade for Cthulhu      |
+-------------------------------+--------------------------------------+

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