Taking Shape

Oct. 1, 2007
Media façade bends, twists, wraps - and redefines what an exterior can be

By Christine Lewers

By day, Uniqa Tower in Vienna, Austria, sits still, as any building would. The transparent-glass, double-skin tower rises as a slender ellipsoid intersected by an angular edge that expands gently outward as it reaches toward the sky.

By night, however, the building comes alive as its 180,000 LEDs light up the sky with media that wraps and bends lines, shapes, and words across virtually every edge of the building's exterior. The LEDs create the impression that the building slowly dissolves, then rises back up from the ground as the lights "rebuild" the tower's surfaces. Or that wind, represented by lines, is ruffling the face of the building like a breeze over sails. Sometimes the building gently shimmers like the river beside it or looks like a huge sculpture twisting and turning on its axis.

The tower, completed in 2004 and designed by Austrian architect Heinz Neumann, is the headquarters of European insurance giant Uniqa. It sits on the Danube Canal between the famous Urania Planetarium and the Ringstraße, a physical link between the city's old section and new.

"They weren't quite sure what they wanted," says Licht Kunst Licht project manager Stefan Hofmann, whose firm won Uniqa's design competition for the media-façade commission. "Our idea was to use the whole building envelope as a screen for content designed to interact with the building's volume. We could change the look by playing different works around the whole building with no start and no end, so that it (content) looks like it is integrated."

The resulting 81,000-square-foot media façade marries video and architectural form in the first permanent LED installation to wrap entirely around a building's surface. 

LKL's design rests on using the cavity of the double-skin construction as a place to hide and protect a wide-meshed grid of LEDs, which together wash the building's surface with a digital-video-quality signal of 25 images per second.

The media artists group Mader Stublic Wiermann, Berlin, created and produced a 30-minute looped artistic video, "twists and turns," that uses two simple motifs, a line and an amorphous form, to create new impressions of the building. To do this, they developed the video directly in relationship to the building's shape, rather than using the LEDs merely for advertising or other content developed independently of the architecture.

And although the media façade is massive, it's not over the top. That's because Mader Stublic Wiermann considered how the special content would affect the building's setting and viewers.

Sometimes Uniqa Tower gently shimmers like the river beside it or looks like a huge
sculpture twisting and turning on its axis.

Hidden LEDs
Such an achievement wasn't simple. The media façade was designed after the building was up and running. Licht Kunst Licht's proposal was required to respect the integrity of Neumann's transparent glass façade and the daylighting it provides occupants. In other words: Give us a light show at night, but don't let us see any lighting equipment on the outside of the building during the day.

Serendipity played a role here. The façade's double skin was designed to create an energy-saving buffer zone against climate extremes and allow for natural ventilation. The two transparent-glass skins are set 20 inches apart and are compartmentalized with flooring. From the standpoint of a media façade installation, the cavities provided ready-made places to hide and protect the LEDs, and the inner skin's operable windows allowed crews to access the space, says Hofmann.

Hidden within the double façade are 44,800 Barco MiPix. The LEDs are installed along the vertical window profiles of the tower's inner shell in long, narrow cases custom-made by Barco to be slightly thinner than the window profiles so that they would be invisible from outside, says Barco project manager Andreas von Erdmannsdorff. Each case is easily removable for maintenance. The LEDs' small size are a big plus, too. The MiPix housings measure 1½ by 1½ inches and hold four individually controllable, full-color pixels. The MiPix were grouped into sets of 16, attached to strips of aluminum at 3-inch intervals, and encased in IP65-certified tubing.

"MiPix is normally an indoor product," says von Erdmannsdorff. "The conditions we had here were more intermediate, so we needed a housing to protect the LEDs."

The tubes hang on the façade's window profiles with clips also designed and made by Barco specifically for this project. In all there are more than 2,800 of these vertical cases attached inside the building's skin.

In addition to the LEDs, crews placed 373 MiPix controllers on the flooring between the façades in a position where the curtain wall construction hides them from exterior view. Cable trays carry wiring to connect the controllers, with all data and power lines gathered to pass through the inner façade into the building at a single point. A central digitizer that accepts video signal feeds it to the controllers.

Except for several moments when the word "Uniqa" wraps itself around the tower's faces,
the shapes and lines that envelop the building are without literal meaning but are an
organic part of the architecture.

From 2-D to 3-D
With the lights in place, Mader Stublic Wiermann worked on location to fine-tune their ideas, keeping in mind how the public would perceive the finished product.

"It was simple to propose," says Mader Stublic Wiermann's Alexander Stublic, who produced a computer-generated 3-D model of content ideas to submit with the lighting design entry. "But once the competition was won, we really had to think about it. How would we bring this idea into reality? There's a big difference between a computer model and the real thing. The biggest thing is the dimension. No computer visualization could give the impression of standing in front of the building."

Part of the challenge was how to project video, which is traditionally a two-dimensional medium, over a three-dimensional object without distorting the image, says Stublic. There's no ready-made software on the market that can handle this problem, he says. In addition, the LED grid is not completely uniform; the lights are spaced apart about 4½ feet horizontally and the media façade comes into focus at about 100 feet away.

All this posed problems with the video that needed to be fine-tuned on location. Mader Stublic Wiermann professionals worked at night to test their work on the building and made adjustments to the video file based on what they saw. The resulting video makes no sense on a computer screen or TV monitor. It only works when the file is reinterpreted by the building's volume, says Stublic.

Another consideration for them was public perception. Because Vienna is an old European city not inundated with advertising images and bright lights, lighting and content designers had concerns about the public's acceptance of a media façade on a building of this scale and prominence.

"We completely concentrated on the building," says Stublic. "The video is not emerging from the building but instead it's focused inward," because it is relating to the architecture. In this way, he says, the content doesn't force itself on viewers and the environment, like advertising often does. Also, unlike modern TV's fast-paced editing style, this production is without cuts altogether. It's a seamless, flowing, omnidirectional work. Color, too, is restrained, limited to soft yellows and blues, despite the fact that the LEDs are capable of producing a nearly infinite variety of bright, intense colors.

Except for several moments when the word "Uniqa" wraps itself around the building's faces, the resulting shapes and lines that envelop the building are without literal meaning but are an organic part of the architecture.

How does such video content help Uniqa build its brand?

"We wanted to create a company that distinguishes itself with quality, future orientation, openness, and flexibility," says Uniqa board member Gottfried Wanitschek, who directs the company's real estate. An elegant, yet playful, transparent glass tower on the Danube expresses the company's brand. The lights do, too, he says, because they enhance the design of the tower.

But they don't overtake it. And in this case, that's the best advertising bright lights can buy. 

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