Mr. Kundig and his team did. They modeled an elliptical egglike interior on a computer and tweaked it until it was 24 feet high, 22 feet deep and 16 feet wide, to control a beam of light streaming in from above, just as the artist wanted.

“A perfect sphere would simply not have worked,” Mr. Girardoni said.

Partly because of its size, the sculpture had to be placed half inside and half outside the living area, so they decided to clad it with weather-resistant Cor-Ten steel segments welded together; a narrow slot, just as wide as the owner’s shoulders, forms an entryway from the living room.

Inside, the sculpture’s curved wood-and-lath framing is covered with a four-inch thick layer of white slake lime, mixed with straw and horsehair, that immediately offers a powerful sensory experience because of its scent.

“I had not worked with lime before,” Mr. Girardoni said, although it is commonly used in his native Austria. “I met an old builder near my summer studio near Vienna and took a weeklong crash course in old-school plastering,” he said. “The finished lime plaster absorbs moisture just like adobe. It is a breathing skin against which sounds reverberate eerily.”

Mr. Girardoni’s all-white creation — titled “The Infinite Room” because light arcs across its walls all day like a pendulum marking time endlessly — is fitted with an ovoid, featureless, blackened wood platform that represents the absence of light. “People seated inside seem to get a heightened awareness of being alive because of the changing light and the acoustics,” Mr. Girardoni said. “Some guests slip inside to chant or meditate. Others cry when they can hear echoes of their breath behind them, and still others beg to leave.”