Conceived as a skylit, sonorous room â a temple dedicated to the sun â it was to have âboth mass and void, fullness and emptiness,â Mr. Girardoni said. âLight and shadows affect the way we perceive things. To prevent shadows, the room needed to be without any corner geometry.â In essence, he wanted an empty chamber with curved white walls and a vaulted ceiling with an oculus.
âI began to work from the inside out, but I really did not know how to make such a structure large,â Mr. Girardoni said.
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.
âA perfect sphere would simply not have worked,â 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 ownerâs shoulders, forms an entryway from the living room.
Inside, the sculptureâs 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.
âI had not worked with lime before,â Mr. Girardoni said, although it is commonly used in his native Austria. âI met an old builder near my summer studio near Vienna and took a weeklong crash course in old-school plastering,â he said. âThe finished lime plaster absorbs moisture just like adobe. It is a breathing skin against which sounds reverberate eerily.â