Creating Images in 3 Dimensions
We live in a three-dimensional world, but most of our computing is done in two dimensions on a flat video screen and then printed on a piece of paper. We can’t do much about the geometry of the screen or the paper, but we certainly can find software programs that will create seemingly three-dimensional images on those flat surfaces.
A couple that I’ve recently worked with are DesignCAD 3-D, a $399 engineering drawing program, and Perspective Junior, a $149 program for producing graphs.
I can hardly claim any expertise in computer-aided design programs, which are used primarily by engineers and architects. But with DesignCAD 3-D, I found it easy to draw three-dimensional objects.
What sets apart a CAD program from a typical computer drawing or painting program is precision. Its purpose is not to create attractive pictures on the screen or on paper, but to produce accurate drawings of objects that may be constructed from such plans.
DesignCAD 3-D normally displays your drawing in four views simultaneously. The central view, which covers the largest portion of the screen, shows the object in perspective, as it would be viewed from above and off to one side so that you can see its depth. Stacked along the left side of the screen are three smaller display windows that show the drawing head on, from the side and looking down from above. The right margin of the screen is a list of the program commands.
Objects are drawn by setting points on the screen and commanding that a line, arc, circle, box or another geometric shape be drawn to connect them.
Because the program draws in three dimensions, you can move the cursor away from you or toward you in addition to up, down, right or left. The perspective view makes it easy to see what you are doing. The cursor is best controlled with a mouse or digitizing tablet, but a keyboard alone will work.
A tutorial exercise gives a good feel for the program’s power as you draw a three-dimensional goblet. It is done by drawing one side of the goblet and then commanding the program to “sweep” that shape around a circle, giving you a picture of the full goblet. It happens quite fast, even on a standard PC/AT, if you ask for only a crude rendition. The smoother the curves (by defining them with more points) the slower it is displayed.
You also can command the program to remove “hidden lines” from the image, so that it looks more realistic. Hidden lines outline parts of the object that normally wouldn’t be visible when the object is viewed from a particular angle. The most realistic display is when you have the program “shade” the image as if it were being lighted from one or more angles.
An accessory for your computer called a math co-processor, which goes inside the machine, will speed things up considerably. Of course, the faster the computer you can afford, the better the program will run.
All drawings reflect mathematical formulas and calculations that define the relationship of the many surfaces of an object to each other. The most impressive feature in the new version 2.1 of DesignCAD 3-D is one that can take into account, for instance, the hollow space inside a section of tubing or a hole bored through the head of a nut, by mathematically subtracting the empty space from the solid. Once those complex mathematical relationships are defined, the resulting overall object can be rotated in any direction and always be rendered accurately.
Perspective Junior is the latest incarnation of a unique graphics program from Three D Graphics in Pacific Palisades. The predecessors were Perspective and BoeingGraph.
It presents data in any of 13 basic three-dimensional graph formats in which parallel lines converge toward a vanishing point in true perspective. For those cases where a two-dimensional graph is better, the program offers eight choices.
Complex sets of data are best graphed in three dimensions to see their relationships. An example would be annual sales figures for 20 sales districts over a 10-year period. Done as a traditional bar or line graph, it would be too confusing to see relationships and patterns. But viewed as a three-dimensional array of bars--sales districts along one side of the cube, years along the base and sales amounts depicted by the height of each bar--the big picture is easy to see.
Data can be imported from popular spreadsheets or typed into a small spreadsheet table. A $69 software option adds 20 kinds of math functions to that spreadsheet sufficient for many calculations.
There are standard versions of each of the three-dimensional graph formats, including various kinds of shapes--bars, blocks, columns, pyramids, ridges and topographical charts. Each can be infinitely customized to get just the viewing angle, size, page placement, color and shading that you want. Text labels are easily added.
Finished charts can be printed on dot matrix, ink jet and laser printers in black-and-white or color. With the software option, you can also use plotters or the Polaroid Palette slide maker.
Perspective Junior is easy to use. Available commands at each step of the way, and the keys to execute them, are displayed on the screen.
THE PROGRAMS
DesignCAD 3-D is a $399 three-dimensional engineering drawing program.
Features: Allows drawing of wire-frame and solid three-dimensional objects in exacting scale, with hidden line removal. Shapes can be subtracted from one another for holes and hollows. Multiple light sources to illuminate shaded objects. Patching and blending of complex surfaces. Print on dot matrix or laser printers or plotters.
Requirements: IBM PC/XT or compatible with at least 640 kilobytes of memory, a hard disk and a graphics display. Expanded memory can be used. Mouse or digitizing tablet preferred but not required.
Publisher: American Small Business Computers Inc., 327 S. Mill St., Pryor, Okla. 74361.
Phone: (918) 825-4844.
Perspective Junior, a $149 business graphing program that shows data in three dimensions.
Features: Contains 13 kinds of three-dimensional charts and eight two-dimensional charts, which can be infinitely customized for viewing angle, color and shading. Optional $79 accessory software adds math functions to program’s spreadsheet and ability to use 80 kinds of plotters and the Polaroid Palette slide maker. Receives data from spreadsheets and sends finished graphs to desktop publishing programs such as Ventura Publisher and Aldus Pagemaker.
Requirements: IBM PC or compatible computer with 512 kilobytes of memory, a graphics display and hard disk.
Publisher: Three D Graphics, 860 Via de la Paz, Pacific Palisades, Calif. 90272.
Phone: (213) 459-7949.
Computer File welcomes readers’ comments but regrets that the author cannot respond individually to letters. Write to Richard O’Reilly, Computer File, Los Angeles Times, Times Mirror Square, Los Angeles, Calif. 90053.
