The experience can be unnerving. You walk past a bank of monitors and they light up. You turn around, and they show a person staring at you. You wave a hand, and the person waves back. Before long, you’re interacting with a set of screens you’ve never seen before.

Get used to it. Every day, exclusive firms are building bigger and better installations for tradeshows, museums and public places. They include room-sized tables with multiple overhead projectors, faux holograms floating inside storefronts and things far more bizarre.

For example, Berlin’s ART COM recently built a sidewalk along a pool in Tokyo that senses footfalls and creates a virtual “wave” across a row of screens lying underfoot. When the wave reaches the edge of the sidewalk, another mechanism sends ripples across the pool. At the Mirage in Las Vegas, Cambridge-based Small Design Firm has decked out a lounge with tables that react to whatever touches them. Place a drink down and they produce a circle; run your fingers along their edges and a colorful pattern emerges.

The potential for such installations is endless. Stores, universities, cultural institutions, private corporations and top ad agencies are only now discovering them. But within a few years, many believe, they will even be found on the sides of buildings.

“It’s not one of those things that is going away,” says Eduardo A. Braniff, ceo and creative director of Imagination USA. “Companies are seeing the benefit. They’re seeing people interacting with their brands longer and connecting with them better.”

THE BACKGROUND
Why all this, and why now? After all, the first generation of kiosks and large-format video displays were not very successful. Thousands of standalone touch screens now stand idle in museums. And a quick walk around any tradeshow floor demonstrates that videos are not particularly effective—when they’re competing with dozens of others.

In part, the reason is technological. In the past few years, screens and sensors have gotten better and cheaper. Where early kiosks could only accommodate a single person, now, it’s financially feasible to have dozens of led displays activated by multiple users at once.

“There’s been a real shift away from individual interaction with a computer to a complete view of what interactivity is,” says Ralph Appelbaum, ceo of Ralph Appelbaum Associates.

For example, museums have begun using overhead projectors to create interactive tables that are far more effective than their stand-up predecessors. Not only does a table fill the center of a room, it also provides a way for many people to get involved at the same time. Outstanding examples include one done by Small Design Firm for the Churchill War Room and another by Ralph Appelbaum Associates (produced by Second Story Interactive) for the National World War One Museum.

Among advertisers, who have less information to convey, the focus has been on large, eye-catching experiences. Typically, these installations use high-powered projectors, filtered glass and infrared sensors to create highly immersive experiences. Placed virtually anywhere that people go—storefronts are one of the more common locations—they allow people to contact brands in three dimensions.

At the Samsung Experience in New York’s Columbus Circle, Imagination designed an entire store with nothing for sale. Instead, customers walk in and play with interactive objects and products. They can create art, explore the city and (of course) talk with experts on Samsung products. Wherever they go, their paths are recorded using a RFID chip and then transferred online, where the experience can be continued.

“It’s very ambient and not a very directly explicit experience,” explains Damian Ferrar, design director of the media group at Imagination. “We’re working on creating interactive exhibits that work on a number of different levels.”

REACTION VS. INTERACTION
So how do we break down this new type of media? Its designers make a distinction between interactive and reactive experiences. The first is relatively straightforward. In it, users are brought in by an “attract” screen and then interact with the content through an easy-to-use (in theory, anyway) interface.

But today few large-format installations are purely interactive. Instead, they feature at least some elements that react as a user moves near them. They may sense a visitor’s presence through an infrared sensor or pick up a RFID signal from a card he or she is carrying.

“We call it a reactive installation if something is reacting to you and you don’t have to interact with it on purpose,” says Joachim Sauter, head of design at art com. “So people say there is something that is reacting with me, and how do I interact with it?”

In their pure form, reactive installations dramatically reduce the learning curve of traditional kiosks. For instance, visitors who walk through Small Design Firm’s Nobel Field automatically set off hundreds of small lights. The rest of the installation consists of screens that play videos whenever someone stands before them. There is no interface as such.

And it’s not merely self-running installations. Especially in Europe, firms are also exploring new ways to enhance public spaces and spectacles. A good example of this is ART COM’s Mediales Bühnenbild, where actors in an opera are automatically tracked by projectors that train video images on them (but not on anything else).

DEVELOPMENT
Obviously, the more advanced of these projects require technical skills that are beyond the reach of most interactive firms. Much of the groundbreaking work in the field is still performed by a small number of specialized companies, many of which have academic connections. David Small, the principal of Small Design Firm has a PhD from MIT and strong connections there; while ART COM’s Joachim Sauter is a professor at the Universität der Künste Berlin. Their productions often involve custom software and an intricate knowledge of sensing and display devices.

Other firms rely on in-house research and development teams. “We’ve got an R&D group here, and we’ll ask them how to achieve an idea,” says Imagination’s Ferrar. “They’ll come back with computers and split them open and hook bits up… A lot of times it involves simple technology, but we use it in a surprising way.”

Even so, the field is opening up. With Flash interfaces, 50-inch LED screens and rudimentary sensors, even inexperienced shops can get into the act. For them, Sauter and Small recommend simplicity. A public installation is never like a Web site, and you should never expect people to wait for something to unfold or to take the time to master an interface.

“The big problem with a lot of installations is that the designer is not aware that there is only an attention span of 30 seconds,” says Sauter. “If the visitor does not understand the interaction principles immediately, he is going away.”

THE FUTURE
From a strategic standpoint, the field remains at that early stage where its practitioners are always looking to build the next big thing. But at least one thing has changed: Now they know there will be a next big thing. And another next big thing after that.

In fact, most of the field’s top designers are looking forward to the time when they’ll be able to mix interactivity with architecture. With increasingly more powerful projectors and better sensors, that time may not be too far off.

“Display technology is catching up to the things I want to do,” says Small. “You could have a wall that’s not just a wall, but a display for information. So the displays could become part of the architectural surfaces and not seen as distinct computer displays plopped into a space…That transition is going to be very interesting.”

That experience will also be a little unnerving at first. But as with large-format interactive installations today, we’ll probably have to get used to it. ca