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CAD peripherals: hardware enhances design instruction.

Computer-aided design software is highly specialized, differing greatly from standard office-oriented programs such as word processors and spreadsheets. CAD application software mandates high-performance peripherals to support the myriad commands and macros that must be input into the system, as well as the large physical dimensions of the printed output. In addition, being able to see all aspects of a drawing requires adequate monitors, video cards and drivers.

* Digitizers

Digitizers are specifically designed to input graphic information into a computer. They consist of either a hand-held stylus that resembles a pen, or a puck that is similar to a mouse yet has a clear window displaying crosshairs and a section containing a number of buttons. The tablet itself acts like a piece of electronic graph paper with each point on the tablet having its own unique x and y coordinates.

Digitizers are used for tracing flat materials to make a 2D graphic representation on-screen, as well as to select commands. Many tablets have templates that run specifically with CAD software like AutoCAD or VersaCAD. With them, commands and macros can be entered without inputting code.

Manufactured by Hitachi America, Ltd. of Sunnyvale, Calif., the Puma Plus digitizing system has a resolution of 1,016 lines per inch and comes with a power adaptor, interface cables and utility software. A choice of either a stylus pen or a 4-, 12- or 16-button cursor is offered. The 12" x 12" tablet features 100 percent compatibility with AutoCAD, a driver for Windows Version 3.0 and a mouse emulator.

The system runs on DOS, OS/2 and compatible computers, plus Sun SPARCStations and Digital DecStations. Once configured, Puma Plus stores all set-up procedures in non-volatile memory to safeguard against data loss in case of an interruption of power.

Genius, a division of KYE International Corp., is located in Chino, Calif., and produces the GT-1212B Plus. This system contains a tablet, utility software, an AutoCAD template, power adaptor, 4-button puck and a 3-button stylus pen. The utility program includes ADI drivers, while the tablet's resolution is approximately 1,000 lines per inch. GTCO Corp. in Columbia, Md., has a similar product that draws its power solely from the host computer's RS232C port and is available in 11.7" x 11.7" and 12" x 18" models.

The XLC or Xtra Performance Lightweight Compact digitizer series by Kurta of Phoenix, Ariz., is designed for CAD, CAE and mapping. The XLC works with DOS, Apple and Sun computers and comes with a choice of 24" x 36" or 36" x 48" active areas.

* Monitors and Boards

CAD operators need monitors with large screens and high resolution to better view their drawings. Other standard features are non-glare glass; a tilt-and-swivel base; and auto sizing, which re-sizes images to fill the entire screen. The CM-2031 from Aamazing Technologies in Cypress, Calif., has a 20"-diagonal screen and offers 1,280 x 1,024 resolution, one of the highest resolutions now available. The .31-mm dot pitch monitor supports VGA, SuperVGA, 8514/A and Mac II graphic modes.

NEC Technologies of Wood Dale, Ill., manufactures the MultiSync series of monitors, one of the first to display any type of graphic standard automatically. Popular in CAD environments, the NEC MultiSync 5D is similar to the CM-supporting 2031, the same graphic modes with the addition of PGC, and displaying an unlimited number of colors.

Graphic boards are needed to support monitors, and the resolution of the board and monitor should be equal. However, since graphic boards are much less expensive than monitors, as a rule one should invest in a high-resolution, quality monitor and upgrade the video card when needed.

Software drivers included with the boards support various popular applications. Display-list drivers are especially helpful for CAD applications, downloading graphics tasks from the host CPU to the board's co-processor. This frees up the host CPU, creating parallel processing in a PC environment and resulting in much faster zooms, pans and redraws. A number of boards are now bundled with display-list drivers.

#9GX, a graphics board from Number Nine Computer Corp. in Cambridge, Mass., now features POWER9, a display-list driver for VersaCAD/386 Version 5.4. According to Number Nine, in addition to supporting 1,280 x 1,024 resolution, the driver program executes CAD commands up to 25 times faster than lower-resolution cards.

A number of boards are now bundled with display-list drivers.

Other features of POWER9 include a "bird's eye," zoom window that may be overlaid onto the full-page view, plus graphical icons.

* Plotters

Plotters are output devices capable of drawing CAD diagrams on a very large scale. Plotter technologies includes electrostatic, thermal and pen/pencil. Electrostatic plotters run paper across a charged bar, then across a toner bar, so toner is attracted to the paper in the form of the diagram. A vacuum then sucks up excess toner. Thermal plotters operate in the same way as facsimile machines, while pen and pencil plotters contain bars on which a number of colored pens or pencils are attached. Usually, the paper moves under the stationary bar, causing the pen to draw a diagram.

Pen plotters normally take vector data, where two end points that define a line are mapped and a line drawn between them. Electrostatic plotters, on the other hand, take raster data. With raster plotters, each point comprising a line is printed on the paper.

Plotters have memory buffers similar to those found in printers. Information is downloaded to the buffer, thus freeing up computer memory for immediate use. And because CAD graphics are comprised of such large amounts of data, plotter speed is also an important consideration.

Roland Digital Group of Irvine, Calif., has lately released the DXY series of pen plotters, sporting eight self-capping pens, an 11" x 17" plotting area, a plotting speed of 16.5 inches-per-second and a 1MB buffer. The A-B sized plotter is fully HPGL-compatible and has RS-232C serial and parallel interfaces. In addition, the DXY-1200 and DXY-1300 models both have an X-Y coordinate display.

The Mural Plotter 8000 from United Innovations of West Springfield, Mass., is an A-D size pen plotter that can be mounted on a wall for greater visibility in a class environment. With an active area of 25" x 34", the plotter also offers an optional eight-pen automatic pen changer.

* Hybrid Products

An interesting CAD specialty peripheral is the BUG Voice Command System from Command Corp. Inc. of Duluth, Ga. The hardware/software bundle enables operators to initiate blocks, AutoLISP routines, cells and user commands in an application verbally. Each voiced command can represent up to 64 keystrokes.

The BUG System ships with a library of commonly used AutoCAD commands. With the included microphone, the operator says a word or phrase to call up specific functions. During initial training, the user says each word into the voice library three times; adding more commands takes less than 60 seconds.

Annotator is a voice-based note system that works in conjunction with the BUG System. CAD operators select part of a drawing to serve as the subject of a note. Next a voice message is recorded-via microphone-that remains with the drawing file. An icon on the drawing alerts a viewer that a note is present and, when the icon is clicked with a mouse, the referenced segment of the drawing is highlighted and the note played.

Another hybrid item is the Plotter in a Cartridge PE, from Pacific Data Products in San Diego, Calif., which emulates HPGL on laser printers. Plugging directly into a printer, the unit offers 300 dpi resolution and scales graphics to various paper sizes, transparencies or envelopes. According to the manufacturer, plots that take 10 to 20 minutes to draw with a pen plotter can be completed in under 10 seconds with Plotter in a Cartridge PE.

* CAD in Education

CAD technology has filtered down from its niche in higher-education and vocational schools to the high school level, generating a greater need for quality peripheral products for a large base of students. CAD is principally used to teach engineering and art, however it can obviously be utilized in architecture, marketing and advertising courses. With the help of high-performance products, learning CAD can be simplified and easier to understand.
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Author:Greenfield, Elizabeth
Publication:T H E Journal (Technological Horizons In Education)
Date:Dec 1, 1990
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