TITLE: Crystal Dreams
NAME: Nathan Kopp
COUNTRY: USA
EMAIL: Nathan@Kopp.com
WEBPAGE: http://nathan.kopp.com
TOPIC: Imaginary Worlds
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
JPGFILE: nkdreams.jpg
ZIPFILE: nkdreams.zip
RENDERER USED: 
    POV-Ray 3.1 custom build

TOOLS USED: 
    Moray - modelling & scene composition
             spatch - modelling of birds
             wcvt2pov - dxf->raw
             3dwin - raw->udo/inc
             NKFlare 5 - lens flares
             Paint Shop Pro 5 - add name & tga->jpg
             Visual C++ - add photon mapping to POV-Ray ;-)

RENDER TIME: 
    1h 26min

HARDWARE USED: 
    P266 (MMX), 96Mb

IMAGE DESCRIPTION: 


(A world where povray renders true caustics.  Imaginary?  Or real?)

this is my imagination...
  a world of delicate crystal dreams,
    soaring high and diving low...
  dreams that lead beyond this jagged place,
    into a vast unknown land...
  a land of complete mystery,
    just beyond the fog.


DESCRIPTION OF HOW THIS IMAGE WAS CREATED: 


To make this image, I just sat down and started working on it, letting
my ideas flow.  That got me as far as the background, ground plane,
and 'trees'.  Next I built the glass birds in sPatch and placed them
in the scene.  At this point, I got out my pencil & paper and started
sketching some other things that might fit into this world that I'd
created.  Finally, I put it all together in Moray, rendered it with
my custom build of POV, and this is what I got.

Oh, by the way, all of the color in the scene comes from one of three
places:  the fog, the sky sphere, and a fill-light.  Nothing else in
the scene has any color of its own.

Details:

Most of the objects are straight-forward primatives and CSG.

The trees are CSG unions of lathe objects.

The mountains in the background are simply a big box with a nice
pigment.  It's a z gradient with a color_map something like this:
   color_map {  0 black   .5 black   .50001 clear   1 clear  }
Then, I added z turbulence to it, scaled and positioned it correctly,
and some nice looking mountains appeared.

The birds were made in sPatch, exported as DXF files, converted to
RAW files using wcvt2pov, and then converted to an inc/udo combination
by 3dwin.  For some reason, 3dwin would not read the DXF files that
sPatch produced.  I went through all this trouble so that I could
merge the wings with the body.  My custom build of POV has the (limited)
ability to determine if a point is inside or outside of a triangle
mesh, making the merge possible for meshes, though not for bezier
patches.  I wanted to use merge so that the birds would look more like
solid pieces of glass (no inner surfaces).

The lens flares are type 'sparkle4' in NKFlare 5 which comes with the
latest version of Moray.

I tried using radiosity in this scene, but it didn't work too well.
The fill (shadowless) light that I used instead was faster and produced
better results in this situation.

That's all folks... you say I'm forgetting something?  Oh, ya... those
nifty caustic effects!  You'll notice refractive caustics under the
low-flying bird and reflective caustics around the base of the lamp's
stand.

Those were produced by my latest custom build of POV-Ray.  This new
special effect uses a backwards ray-tracing step to determine how
light propogates through the scene, and stores the results in a data
structure called a kd-tree.  The concept, known as the photon map, was
first introduced by Henrik Wann Jensen.  Soon, I should have an
alpha version available for the public to try out.  The syntax will be
different from what you see in my source file, though.

In this image, the backwards ray-tracing (or beam-tracing) step took
approximately 3 minutes.  651,822 rays were traced out of one of the
light sources, and 151,028 photons were stored in the photon map.
(This was probably more photons than necessary, but I wanted to be
on the safe side.)