4.11 Making 3D Slides
Bruce Goren, CIS's resident stereoscopic maven, contributed these tips
on what to do with your 3D images (Bruce inspired and prodded us so much
we automated much of what follows, allowing both this and actual on
screen stereo viewing, but we included it here for reference and a brief
tutorial.)
"I use a Targa 32 video card and TOPAS graphic software, moving the
viewport or imaginary camera left and right to create two separate views
of the stationary object in x,y,z, space. The distance between the two
views, known as the inter-ocular distance, toe-in or convergence angle,
is critical. It makes the difference between good 3-D and headache-
generating bad 3-D.
"For a 3D fractal landscape, I created and photographed the left and
right eye views as if flying by in an imaginary airplane and mounted the
film chips for stereo viewing. To make my image, first I generated a
plasma cloud based on a color map I calculated to resemble a geological
survey map (available on CIS as TARGA.MAP). In the 3D reconstruction, I
used a perspective value of 150 and shifted the camera -15 and +15 on
the X-axis for the left and right views. All other values were left to
the defaults.
"The images are captured on a Matrix 3000 film recorder -- basically a
box with a high-resolution (1400 lines) black and white TV and a 35mm
camera (Konica FS-1) looking at the TV screen through a filter wheel.
The Matrix 3000 can be calibrated for 8 different film types, but so far
I have only used Kodak Ektachrome 64 daylight for slides and a few print
films. I glass mount the film chips myself.
"Each frame is exposed three times, once through each of the red, blue,
and green filters to create a color image from computer video without
the scan-lines which normally result from photographing television
screens. The aspect ratio of the resulting images led me to mount the
chips using the 7-sprocket Busch-European Emde masks. The best source of
Stereo mounting and viewing supplies I know of is an outfit called Reel
3-D Enterprises, Inc. at P.O. Box 2368, Culver City, CA 90231, tel. 213-
837-2368. "My platform is an IBM PC/AT crystal-swapped up to 9 MHz. The
math co-processor runs on a separate 8-MHz accessory sub-board. The
system currently has 6.5 MB of RAM."