At first glance, the new Filene Center II at Wolf Trap Farm Park resembles the park's original theater, which burned to the ground last year. But the new structure, which will open next summer, owes its rustic design as much to the state of the art in computer-aided design technology as it does to its predecessor or its pastoral surroundings.

Using technology that is playing an increasingly large part in the business of architecture, Dewberry & Davis of Fairfax designed much of Filene Center II and produced many of the working drawings to be used in its construction electronically.

The architects used a computerized video display screen rather than pencil and paper to experiment with design options, automate the drawing of repetitive features and to hasten the traditionally laborious execution of detailed mechanical blueprints.

Although the new Filene Center is one of the most spectacular projects yet designed by computer-aided design and drafting (CADD), the technique is being used with increasing frequency by larger architectural firms able to afford the expensive systems. Some experts at the American Institute of Architects (AIA) believe most architects will have traded their drafting boards for computers by the end of the century.

"It liberates the architect and engineer from the labors of drafting," says A. Russell Versaci, the Dewberry & Davis partner who supervised the Wolf Trap project. "There is a point in the creative part of the discipline, the scientific part of the discipline, where the work becomes a tedious exercise, and that's the point where the computer liberates us."

CADD gives architects remarkable design flexibility. Using the computer, the architect can modify a design almost endlessly, without the erasing and redrawing that would be required of a design on paper. The designer can also have the computer "draw" repetitive patterns like brickwork that normally would have taken considerable time.

And in one of the most spectacular displays of the power of the new tool, highly sophisticated systems can produce three-dimensional, computer-generated models of a design on a video screen that can be rotated for viewing from different angles, lighted to represent their appearance at various times of the day, and even "walked through" by the computer, as if a viewer were looking at a film of an actual building.

While Dewberry & Davis says its use of computers cut to four months a design and engineering job on the Wolf Trap project that normally would have taken 12 months to accomplish, the potential applications for CADD could dwarf that productivity gain.

"There are many projects which are not suitable for input onto computers, and also there are projects which are highly suitable," says Michael Konopka, principal associate of Wolfberg, Alvarez, Taracido and Associates, a large Miami-based architectural firm whose CADD system extends to its Rosslyn branch office.

The best-suited projects, experts say, are those based on generic or "cookie-cutter" designs, such as multistory office buildings and condominium developments that repeat a handful of basic unit designs.

"If it's a symmetric plan, if it's a high-rise office building, it's going to lend itself well" to CADD, says David Jordani, a member of the AIA's committee on computers in architecture and manager of interactive graphics systems at Ellerbe Associates, a large Minneapolis-based architectural firm.

"You can really view it as word-processing for drafting. The more repetition on a standard format you have, the more productivity you get," says George Korte, head of computer graphics operations at Dewberry & Davis.

Computerized architecture offers several other potential efficiency gains, such as automatic cataloguing by computer of construction supplies specified in blueprints; the potential for easy updating of plans and maintenance schemes as a building grows older and is renovated, and an instant base for plans for the remodeling of an older building designed by computer.

CADD systems don't come cheap. Dewberry & Davis bought its two-terminal system for $300,000 from Intergraph, a Huntsville, Ala., firm that is one of the leading designers and assemblers of computer-aided design equipment. The CADD workstations at Dewberry & Davis each have two video-screens, a computer keyboard and a hand-held electronic "mouse" that is moved over an electronically sensitive table to "draw" on the video screens. Actual blueprints are then turned out on a special printer, and reproduced in the normal fashion.

Smaller, more simple systems can be had for around $50,000, but even that price is out of reach for most small architectural firms--and the AIA estimates that 80 percent of its 13,000 member firms have 10 or fewer employes.

An AIA survey done a year ago found that about 5 percent of the nation's architectural firms were using CADD. The past year has also brought the introduction of a trade magazine devoted solely to CADD.

"It has caught on like wildfire in the past year," says Versaci, whose Filene Center project has been written up frequently in the trade press. "It's as if architects suddenly discovered that there are computers in the world."

It's not that they didn't know about computers before. At firms like Dewberry & Davis, a 600-employe, 150-architect outfit that is one of the nation's 100 largest design and engineering firms, computers have long been used for stress engineering and other functions, as well as payroll and bookkeeping services. "Computers are not new to engineers and architects," Korte says. "What this system is allowing us to do is automate our drafting."

By no means have computers taken over all the work at Dewberry & Davis. Only six of the firm's employes are trained on the system, although with productivity gains Korte estimates that CADD now accounts for as much as 10 percent of the firm's output. But the experience with Wolf Trap and with some smaller, less-glamorous projects in the past year has shown the firm the power and efficiency of CADD.

Ironically, Dewberry & Davis did not originally intend to use the computer system to design Wolf Trap. When it received the Filene Center II contract last September, the firm intended simply to update the original plans for the structure using conventional drafting techniques. It figured the job would take about four months, and promised the plans for the first of the year.

It soon became obvious, Versaci says, that Dewberry & Davis had underestimated the task. "We quickly found out that the backstage and stage facilities in the old theater were really not convenient," he says. Further, changes in building codes since the original Filene Center was built in the 1960s forced other modifications in the design, as did a fairly obvious need stemming from the original building's fate: "One of the principal concerns in the new design was to make it as fireproof as it could be, but still keep it as woodsy, as outdoorsy-looking as possible," Versaci says. Wood-clad steel replaced the old wooden superstructure, and a sprinkler system was added. Also, the theater was expanded by a couple hundred new seats.

By the time the firm had finished its preliminary work, it found the need for an almost totally new structure, albeit one closely resembling the original. "It would have needed an armada of draftsmen," Versaci says.

So the architects turned to their newly installed computer system, which had been in the building for all of three weeks when it was assigned the job.

Working virtually 24 hours a day--five employes spent Thanksgiving Day slaving over a hot video-display-tube--the firm produced 66 different blueprints for the project, covering basic design, structural components and floor plans. Only the plumbing, electrical and mechanical-equipment plans were conventionally drafted.

"It was an extremely complicated learning exercise, in fact probably the most complicated learning exercise you can have," Versaci says. "It was really trial by fire."

Since then, the firm has designed several other projects on its system, and is planning to add additional terminals. The firm's next major CADD project is an addition to the First American Bank building in Tysons Corner. Versaci says, "It's really a matter of months before we launch into an entire project by computer."

The system proved particularly valuable when Dewberry & Davis did preliminary designs for a new series of service stations planned by a major gasoline marketer. The computer was able to mix and match various modular features that created designs with family resemblances to one another.

Such repetitive projects allow CADD systems to shine. The Wolf Trap assignment, in fact, was not a particularly good illustration of some of the best features of CADD architecture because so many parts of it were unique. Still, should Dewberry & Davis find itself with another outdoor-theater project--and it has been approached about some--Versaci believes that the firm will be able to use the computer to adapt some parts of the Filene Center plans to the new project, as opposed to starting from scratch with conventional drawings.

While CADD systems are expected to proliferate in architect's offices throughout the nation in the next few years, bringing with them changes in architecural education and disciplines, no one is quite yet willing to predict the demise of the traditional image of the architect hunched over a drawing board with pencil, paper, triangle, T-square and French curve. Architecture has always been a labor-intensive business, and the shift to capital-intensity is proving uncomfortable for psychological reasons as well as financial ones.

"There's a long way to go before a transition from manual to automated methods is complete," Jordani says. "It is a fundamental change."

And Jordani adds, "We look at the computer becoming another tool. I don't know if it's going to be the same as going over and picking up a parallel rule and sitting down and staring to draw, but we'd like to see it become that way."