Written by Cong ( Carrie ) Wang
Jan 25, 2005
This project is done by POV-Ray 3.1under Windows XP operating system.
This ray tracing project is based on an image of the ice castle in Lake Louise, AB.
The picture i generated is just horrible, but after all, this is the best i can do.
To draw this image in POV-Ray
1. i have to set up the sence, a flat plane for the ground and an open-ended cylinder for the background.
later on, i changed the cylinder into a sky sphere.
2. set up the camera and the light source on the origin, and then transform the light source to the top,
and the camera to the bottom right.
3. set up the image of the ice castle in the middle of the picture, and move it to the left later on.
the castle is build up with several rectangles and cylinders, and glued together as an object by operations,
such as, intersection, merge, union.
Those steps are easy and straight forward.
4. Modify the texture.
This is the hardest part of this whole project
since the castle is made of ice, which is semi-transparent, so i decide to use the texture defined in the glass.inc.
in order to get the perfect texture, i have to go throught all the possible textures and interiors in glass.inc,
and adjust the fading power, max ray tracing level, and so on.
The final version i choose, includes three light sources, one is behind the castle, and another is in front.
those two light sources partly controls the level of transparency of the glass. in addition, there is the third light
source that puts the shadow on the ground.
original picture.
 the picture i generated based on the picture above.
 source code has been emailed to the marker.
credits:
thanks Kenneth Qiu for the sky sphere.
thanks Sebastian Hanlon for the advices of using anti-aliasing to soft the lines,
adjusting the camera angle to fix perspective distortion, and turning down the lights to bring out
the glass texture.
In all, this picture is not ideal, but it is the best i can do for now.
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