TITLE: Almost Home
NAME: Gary MacKinnon
COUNTRY: USA
EMAIL: gary@mackinnon.com
TOPIC: Winter
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
JPGFILE: jgmwint.jpg
RENDERER USED: 
    Pov-ray 3.5 beta 15

TOOLS USED: 
    Paint Shop Pro to convert to jpg.

RENDER TIME: 
    About a week.

HARDWARE USED: 
    Athlon 1700 with 1GByte Ram

IMAGE DESCRIPTION: 


This scene contrasts the cold, snowy and dreary outdoor environment with the
warm and inviting indoors.  The outside is characterized by cold blueish
pigments, pealing paint and stains on a poorly maintained window.  Inside
pigments are warm and yellow.  There is a roaring fire, carpet and the symbol
of a warm family, a Christmas tree. 


DESCRIPTION OF HOW THIS IMAGE WAS CREATED: 


Well there is a lot here but I will try to be brief.  This is my second IRTC
entry.  This was all done in Pov-ray script.  No modeller was used.  

Outside lighting comes from an area light to soften the shadows.

The falling snow is random prisms with a bozo pigment map of White and
transparent colors. 

The snow on the window sill is an isosurface with noise and trimmed by planes. 


The pealing paint came from a technique that Christophe Bouffartigue used in an
IRTC entry called CBWOR. Unfortumately the dull lighting and the snow
diminishes the visibility of the effect here. 

The frost on the glass is two intersecting isosurfaces with noise functions. 
One surface is a circle modified with low frequeny noise and forms the top
random edge.  The facing surface is a higher frequency noise.  The frost is
semi-transparent. Each panel is different.

The Christmas tree was a challenge. I first thought of modeling every needle but
the tree would require millions.  Instead a segment of a branch was modeled as
a cylinder with a bozo pigment map surface of green and transparent colors.  A
wood colored thin cylinder ran down the the center of the branch segment.  The
branch segments were assembled into branches with some randomness in the
placements and the branches were assembled into the tree again with randomness.
 The effect from a distance was not bad. Something similar was done for the
wreath. 

The lights of the tree were placed somewhat randomly but toward the outer edge
of the tree.  The placement macro also prevented lights from being placed too
close to each other.  Unless you add this check you get unrealistic clusters of
the lights.  The lights had a fade distance of about three inches.  The lights
slow down the rendering tremendously and to keep it from getting completely out
of hand the lights are only placed on the roughly 30% of the tree that is
visible. I tried using the light_group construct to speed up rendering but it
seems to have limited applicability.  It could not see the light bulbs that
were placed using a macro even though the macro was inside the light_group
construct.  Anyway the rendering takes many days on a fairly fast machine and 1
Gb RAM is needed.

The fire is an emitting media.  The density was formed using a function in x,y,z
which created a conic shape which was then warped to create the random flames. 
The density was then painted with a color map ranging basically from black to
red to yellow. 

The sconces were hard to get the effect I wanted. I was hoping to model the
light and material properties accurately and Pov-ray would do the rest but I
ended up having to use some extra lights.  An image map was used for the mica
surface. This was made semi-transparent and at a high ambience. A bright light
bulb was placed inside the sconce to create the bright area that you see on the
mica. However this created unrealistic lighting outside the sconce so the fade
distance was shortened to a few inches and a second light was placed inside the
sconce.  Finally, a third light was placed outside the sconce to effectively
light the surrounding area. 

The light falling on the window and sill comes from another interior light off
to the right.

Appologies for not including the source files but my Pov-ray environment is now
a collection of intertwined include files from which the applicable code for a
single image is not easily extracted. I will be happy to send code fragments to
anyone who inquires about any of the components.







