PC Graphics Gear Up

By Terry Wohlers

Published in Vol. 13, No. 1, January 1994 issue of Computer-Aided Engineering
Copyright 1994 by Terry T. Wohlers

Despite increasing power and sophistication, PCs fall short of the capabilities offered by Unix workstations when running 3D CAD applications. This shortcoming is especially evident when comparing 3D graphics and rendering performance. Consider the time it takes to render objects on workstations and compare that to the most powerfully equipped PC. A shading operation that takes a second on a workstation may take a minute or longer on a PC.

Artist Graphics is working hard to change that. With its powerful Artist Xj1000 board, users can do in a few seconds what used take one to three min. Using the Xj1000, I produced a smooth shaded (Gouraud) rendering of a moderately complex 3D mechanical assembly in 3 sec. Without the board, the assembly took 11Ú2 min to render using standard VGA. A solid model of a pulley took 1.8 sec using the Xj1000 board versus 58 sec without it. A complex organic shape, generated from a 3D laser digitizing system, required just 4.4 sec, compared to 2 min and 36 sec.

The Technology

The Artist Xj1000 product gets its power from the GPX hardware, a chip designed specifically to accelerate CAD display operations. Through built-in Gouraud shading, the chip is capable of generating 16,000 shaded triangles/ sec, 240,000 3D vectors/sec and 600,000 2D vectors/sec. This performance approaches the capabilities of workstations priced between $26,000 and $37,000. They generate in the range of 20,000 to 23,000 shaded triangles/sec and 400,000 and 820,000 3D vectors/sec.

Artist Graphics has developed software called 3D RealTime that taps the power of the GPX chip. Without it, you could not take full advantage of its 3D capabilities. The 3D RealTime software reads 3D entities from within AutoCAD R12 or MicroStation 5.0, stores them in memory on the board and draws them in a window on the screen. This approach enables you to rotate 3D models and quickly produce smooth-shaded renderings. While 3D operations are indeed fast, I found that 3D RealTime can take up to a minute or more to initially load the 3D data in AutoCAD. For example, 3D RealTime took 1 min and 20 sec to load the organic shape. Once the data has been loaded, however, you can create an unlimited number of 3D views in seconds.

To use 3D RealTime, you must equip the Xj1000 with one or more megabytes of DRAM (memory). With one megabyte, 3D RealTime produced a 7-in. (diagonal) window on my 21-inch Toshiba monitor at 1,280 3 1,024 resolution. The AutoCAD drawing, menus, etc., remain on the screen in the background. Two megabytes of DRAM are required if you want to display the image contained in the 3D RealTime window across the entire screen at this resolution.

Supported Software

The Xj1000 and display drivers support AutoCAD 10, 11, and 12, MicroStation 4.0 and 5.0, 3D Studio 2.0, and Animator Pro. While 3D RealTime works with AutoCAD Release 12 and MicroStation 5.0 only, the Xj1000 enables you to display up to 256 colors at 1280 3 1,024 resolution using any of these software products. Additionally, you can display 16.7 million colors at a resolution of 800 3 600 with software that support 24-bit color, such as 3D Studio, Intergraph ModelView, and Windows software that supports true color. Changing from one resolution mode to another is handled with special software from Artist Graphics, so there's no need to open the computer and change switch settings.

The Xj1000 also ships with a Windows driver, so all Windows 3.1 applications operate in whatever high resolution mode you choose to set. A resolution of 1,280 3 1,024 made the display of Windows applications on my 21-in. monitor unusually crisp. Also, the high resolution granted more screen real estate than ever before, enabling me to open and arrange an impressive number of windows at one time. According to Artist Graphics, the Xj1000 and Windows driver accelerates Windows functions by up to 20 times over standard VGA. I noticed an improvement of Windows speed after installing the board, although I did not run any tests to check performance.

The DOS command line and all DOS applications that support VGA appear at the standard 640 3 480 resolution. This makes the board compatible with nearly all software. Text and graphics, however, are anything but crisp at this resolution on a 21-in. monitor.

Terry Wohlers is an industry consultant who helps organizations select, implement and manage technologies for CAD/CAM/CAE, rapid prototyping, and reverse engineering. He works out of Ft. Collins, CO.

Copyright 1994 by Terry T. Wohlers


The Graphical PC

It looks like 1994 is going to be an exciting year for PC graphics. New buses, chips, boards, hosts, and software promise to make PC graphics shine.

Buses are changing quickly as PC CPUs skyrocket in speed. Today, the VESA local (VL) bus approach is fairly standard for PC graphics, connecting the graphics processor directly to the CPU to transfer 32 bits of data at speeds of up to 33 MHz. But Intel has come up with what it thinks is a better solution: Peripheral Component Interconnect (PCI) bus, designed with the Pentium to link graphics accelerators and other peripherals to PCs. Although PCI graphics cards are not much faster than VL-bus versions, some believe PCI may eventually win out thanks to its Pentium ties and the fact that PCI will work with processors other than those made by Intel.

Another factor in making PCI successful, however, will be the availability of boards. That seems assured as many board makers are hopping on the PCI bus. Hercules Computer Technology Inc., Santa Clara, CA, offers the Hercules Dynamite PCI Pro. Said to be the first to use the Tseng Labs ET4000/W32p chip, this board uses a memory interleave technique to increase performance while sticking with less expensive DRAM memory. It sells for $299 in a 2 megabyte version.

Also joining the PCI bandwagon is a quasi-new entrant into the graphics board field: miro Computer Inc., Santa Clara, CA, the U.S. arm of a large German maker of PC graphics boards. One claim to fame: the firm offers identical pricing for ISA, EISA, VL, and PCI boards, with prices ranging from $229 to $899.

Is there 64-bits in your PC graphics future? It's likely. Matrox was one of the first in this arena with its 64-bit MGA chip and boards. Now, the firm has introduced a lower cost series of accelerators built on the second version of its 64-bit chip. Made for VL and PCI buses, the MGA-II series is said to be ideal for 2D CAD users. Prices with two megabytes of VRAM start at $599. The firm still offers the MGA-I line (Ultimate, Impression, and Pro) for 3D CAD users. These accelerators come in ISA, VL, and MCA versions and start at $849.

Also joining the 64-bit brigade is Infotronic America, Austin, TX. Its IGP-64 line of accelerators based on the firms proprietary 64-bit chip. These boards are said to provide 4 to 12 times the speed of conventional 32-bit processors and are available for ISA, EISA, MCA, VL, and PCI buses. They are also upgradeable with the firm's shading processor for fast rendering inside AutoCAD, Microstation, and Windows. Prices begin at $899. What's more, graphics chip maker S3 Inc., Santa Clara, CA, recently unveiled its Vision family of 64-bit accelerators. The firm believes CAD users in 1994 will demand 64-bit accelerators with 1, 280 3 1,024 resolution and 65,000 colors (or 1, 024 3 768 with 16.7 million colors). OEMs using S3 chips today include Dell, Digital, IBM, NEC, Diamond, Number Nine, and Orchid.

In fact, STB Systems, Richardson, TX, is already offering boards built around the new S3 chips. The Powergraph Pro ($449 in a 2-megabyte version) and the Pegasus Pro ($999 in a 4-megabyte model) are both PCI-based boards. These accelerators are part of a product lineup that begins at $199.

Drivers-software that interfaces CAD programs to the graphics hardware, often provide additional functions along the way-are important in PC graphics. For instance, Vermont Microsystems Inc. (VMI), Winooski, VT, is continuing its transition to a focus on software. The firm has aligned with ELSA GmbG of Aachen Germany. VMI will concentrate on its AutoMate software, a series of drivers for improving AutoCAD performance, while ELSA supplies the hardware and resells VMI's software in Germany.

PC graphics boards will be moving into workstations, thanks to Windows NT. For instance, Appian Technology, Sunnyvale, CA, says its Renegade accelerators and drivers now support Windows NT on Intel, Alpha, and MIPS platforms. The Renegade uses Appian's proprietary graphics chip a and is said to be designed for CAD acceleration as well as Windows. Prices start at $450.

By Robert Mills, Editor, Computer-Aided Engineering.

Acronym Guide

A few terms commonly used in describing graphics accelerators:

VL: VESA Local Bus. A 32-bit bus specification put forth by the Video Electronics Standards Association (VESA). Most often used for graphics boards; most new PCs provide VL bus along with ISA (Industry Standard Architecture) or EISA (Extended ISA) bus slots.

PCI: Peripherals Component Interconnect, a new bus designed and promoted by Intel to better match today's high-speed CPUs. PCI is an alternative to VL bus.

VRAM, DRAM: Video RAM and Dynamic RAM. Memory added to a graphics board. VRAM has two data paths, DRAM has one; hence, VRAM generally makes for faster, albeit more expensive, graphics (new designs are helping to make DRAM boards perform almost as fast as VRAM models). Resolution, number of colors, maximum refresh rate, and speed are all related to the amount of memory available.