../fish.jpg Jerry's Raytraced Images

Raytracing is a method of creating high-quality computer-generated images. These images were created using Craig Kolb's Rayshade, which I ported to the Macintosh using Think C.

If you use AOL 3.0, make sure you turn off compressed images in the web preferences, or download the images, to avoid ruining the image quality.

Different image sizes are provided for use as Macintosh Desktop Pictures. Pick the version with the size and color depth that best matches your Monitors settings. Using the right size will avoid "jaggies" that result from resampling the image to match your screen dimensions. Using the right color depth will give you the best looking picture by avoiding color quantization effects. Images are intended to be displayed in 24-bit color ("millions") unless otherwise noted. Those noted as 16-bit color are actually stored in 24-bit color (since they are still JPEG files), but have been pre-dithered so they look good on a 16-bit display. For some reason Desktop Pictures doesn't do a very good job of dithering a 24-bit color image to 16 bits without this little bit of help.

Copyright 1998 Jerry Farm
These images are free for non-commercial personal use; I retain all copyrights.
These images may not be redistributed without my permission.

thumbnail Snowman (by Alan Kilian and me)
400x400 GIF (22K) for 8-bit color
Shows surface textures and shadows.
My first raytraced scene.

thumbnail Aquarium
640x480 JPG (99K)
640x480 JPG (129K) for 16-bit color
1024x768 JPG (137K)
(No 8-bit version -- it does not look very good with 8-bit system colors)
Shows refraction, reflection, wood grain, bump, and other textures. The aquarium started out as an experiment to see how well a raytracer could capture the refraction effects observed in an ordinary 10 gallon aquarium. The project then took on a life of its own as fish, plants, bubbles, an LCD thermometer, and other details were added to the image. It took about 200 hours to set up the input files to Rayshade, since the models were created primarily with a text editor, and a Mac II was used to generate test renderings (this was back in 1990). Also the scene is moderately complex. Several programs were written in C to generate the various plants and the masses of bubbles. To get a fairly realistic image, a great deal of experimentation was required adjusting the colors, textures (wood grain, granite sphere, sand, fish scales, water surface), lighting (two light sources in the aquarium light and one in the room), and the reflectivity and transmissivity of the glass and water.

Once the models were completed, Alan Kilian and I took them into Cray Research (where he worked at the time) and did the final rendering on a Cray Y-MP. Due to the large number of reflected and refracted rays this scene required, the rendering took 18 hours for the original 1280X1024 stereo images. The stereo pair appeared in the ACM SIGGRAPH '90 Stereoscopic Slide Set (1990).

The 1024x768 version of the image was created by scaling the original 1280x960 mono image by 2, effectively oversampling it to 2560x1920, and then scaling by 0.4 to get 1024x768. This avoided jaggies (aliasing artifacts) that appeared if the image was simply scaled by 0.8.

thumbnail Raytracers' Recess
640x480 JPG (76K)
640x480 JPG (110K) for 16-bit color
640x480 GIF (83K) for 8-bit color
832x624 JPG (93K)
1024x768 JPG (115K)
Two versions of Raytracers' Recess were rendered, a high quality monoscopic image (shown here) and a lower quality stereoscopic pair. The original 1800x900 mono image took 213 hours to render on a Mac II. 67 million rays were traced including eye, reflected, and shadow rays. Anti-aliasing was provided by subdividing each pixel into a 4x4 grid of subpixels. Soft-edged shadows were obtained by tracing multiple shadow rays to an area light source. The stereo pair used a point light source rather than an area light source, reducing the number of shadow rays to greatly speed up rendering.

In addition to the background, three other walls, a ceiling, and a door enclose the scene. Even though they are not directly visible, they greatly improve the realism of the scene by adding realistic reflected highlights in the chess pieces. A wide-angle reflection of the room can be seen in the head of the black pawn on the left.

To create the characters in the scene a small C program guygen was written which accepted a list of arm and leg joint angles and created Rayshade-compatible input files. You can download the files for Raytracers' Recess from this BinHex'd Stuffit archive (30K). The archive includes the Rayshade input scene file, plus the source to guygen and it's input files.

For more details, see the Raytracer's Recess Design Notes.

The mono image appears on the cover of the book Computer Graphics, Second Edition, Hearn and Baker, 1994. The stereo pair is also in this book on p. 50, and shows up again in Computer Graphics C Version, Second Edition, p. 50, Hearn and Baker, 1997. The stereo pair appeared in the ACM SIGGRAPH '92 Stereoscopic Slide Set (July 1992).

These versions of Raytracers' Recess have a white bar across the top which is hidden by the menu bar when they are used as desktop pictures on a Macintosh.

Updated: 24 Feb 2000

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