L.A. gets a piece of Vegas attraction action: firms that once built movie sets now making thrill rides.

Las Vegas and Los Angeles are two cities joined at the hip pocket - the one where the wallet is kept.

A recent explosion of entertainment-oriented resorts in the desert city is fueling a parallel growth in L.A.'s themed entertainment and multimedia industries.

Los Angeles-area companies that once designed sets for motion pictures or TV shows - or built computer systems for the military - have turned their talents to the creation of spectacular themed environments, such as the newly opened New York-New York hotel and attraction.

They are designing entire fantasy atmospheres, or contracting for little pieces of them - such as the computer-linked, moving "windows" being created by Burbank-based Metavision Corp. for the upcoming SpaceQuest Casino at the Las Vegas Hilton. The attraction will create the illusion that one has entered a space station orbiting the earth using actual NASA images and Hollywood-style special effects.

Then there is the Grand Prix attraction being designed by Westlake Village-based Illusion Inc. for the Sahara Hotel and Casino, which will link 24 would-be Al Unsers in scale-model racing cars for a virtual reality automotive duel.

Trying to quantify the growth of L.A.'s themed entertainment industry is difficult, but one measure is the increasing membership of the industry's trade alliance headquartered in Burbank, the Themed Entertainment Association.

According to its president, Peter Chernack (also the president of Metavision), the group had 160 members two years ago and now boasts 360.

Although Florida, New York and Chicago are seeing expansion in the themed entertainment category, Chernack says about 60 percent to 70 percent of the association's members are located in Southern California - with a dense concentration in the San Fernando Valley.

Some of the bigger local entities include Burbank-based Iwerks Entertainment Inc., which specializes in motion simulator rides (capsules on a hydraulic platform fronted by a movie screen, such as the "Star Tours" ride at Disneyland), attraction designer Landmark Entertainment Group, based in North Hollywood, and Culver City-based motion simulator builder Showscan Corp.

Other companies do everything from creating video games to building realistic fantasy scenery. They consist of architecture firms, computer network specialists, Hollywood special effects designers, set builders and a range of other specialties.

Chernack says his association has identified 57 different disciplines among the group's members.

"Themed entertainment is an expanding market, because it's not limited to the Disneys and the Universals and the Knotts Berry Farms anymore," Chernack said. "The amount of development that's going on in Las Vegas is tremendous."

All told, there have been about $10 billion worth of investments in hotels/attractions in Las Vegas since 1989 - and another $6 billion will be spent within the next two to three years.

Ever since 1989, when developer Steve Wynn opened the Mirage, the mix of attractions in Las Vegas has undergone a profound shift. From a gambling mecca, it has become a series of entertainment-oriented hotels and malls intended to attract families as well as adults.

Los Angeles was the logical place to find people to design these attractions, because of the broad range of companies here that support the entertainment industry.

When Sunland-based Lexington Scenery and Props Inc. was founded 13 years ago, it built sets for TV commercials and the occasional B movie. Then, about five years ago, it won a contract to make the Treasure Island casino/resort look like a pirate village.

Today, Lexington does about 30 to 40 percent of its business in Las Vegas. It recently constructed the cityscape environment in the food court at New York-New York.

"There's an interesting mix in this business," said Lexington President Frank Bencivengo. "You have one foot in the theatrical world and one foot in the contracting world."

The Las Vegas boom also provides employment for former military contractors in an era of defense downsizing.

In the 1980s, the principals of Illusion Inc. helped design the $250 million SIMNET system now used for training exercises by the U.S. Army. The virtual reality network allows soldiers from around the world to engage in interactive war games by connecting through computers over phone lines.

Last summer, Illusion won a $10 million contract with the Sahara Hotel in Las Vegas to design the main attraction for its renovation. Illusion is now creating the virtual reality network that will link 24 scale-model Grand Prix cars together.

The result will be an interactive motion simulator ride unlike anything ever built, in which people inside cars moving on hydraulic platforms fronted by large projection screens will seem to be racing against each other on a computer-generated track.

Matt Walton, executive vice president at Illusion, said the company has shifted from taking about 70 percent of its revenues from military, contracts in 1995 to only 40 percent last year. By the end of 1997, it expects to be doing 70 to 80 percent of its business in entertainment.

The Las Vegas boom is fueling growth not only at companies considered traditional multimedia or entertainment firms. Such fields as architecture and construction are also seeing a shift.

"When we first started in entertainment, there were very few architecture firms doing this kind of work. Now, almost every major firm has an entertainment division. The competition is getting very tough," said Rick Solberg, vice president of The Cunningham Group/Solberg + Lowe architectural firm in Marina del Rey, which is currently designing the structure that will hold a "Star Trek"-themed motion simulator attraction at the Las Vegas Hilton.