OTTO Piene, who has died aged 86, was a conceptual artist known for his gigantic open-air sculptures. He was most famous for his Olympic Rainbow, which consisted of coloured tubes that lit up the sky at the end of the 1972 Munich Olympic Games. His work has been exhibited in more than 100 galleries and museums worldwide.
He was born in Bad Laasphe in Germany, the son of a physicist, and studied art at the Hochschule für Bildenden Künste in Munich and the Staatliche Kunstakademie in Düsseldorf. He also studied philosophy at Cologne University.
His first medium was paint but he became interested in light early on in his career and in the late 1950s founded the influential Zero Group of artists with colleague Heinz Mack. The word zero was thought to refer to 1945 as Year Zero and was designed to redefine art after the Second World War. Piene once said that "zero was about the pure possibilities for a new beginning". "Artists after the war turned against technology, because war is technology," he said.
From 1959, the year in which he had his first one-man show in Düsseldorf, he worked on The Light Ballets in which light from moving torches was projected through moving grids, and also became known for a series of smoke pictures in which Piene burned paper and then created pictures using the soot. He also developed what was known as the Grid Picture, a type of stencilled painting made from half-tone screens.
In 1972, he created his most famous work for the Olympic Games of that year by filling different-coloured tubes with helium and using them to create a strip of rainbow that lit up the sky. Following the Palestinian terrorist attack on the athletes' village, Piene's work was seen as a symbol of hope.
Piene, who called the work Sky Art, said "people really got the feeling that there was a reason to hope, that not everything from now on would be disaster, death and destruction".
He followed the Olympic project with other large-scale works, including Lighter Than the Air in Paris, which was made of tubes arching across each other, and the sculpture Superstar in Berlin. All of them used Piene's favourite medium of light.
"To praise light alone does not seem enough for me," he said. "I take hold of the darkness itself and shine light through it. I make it transparent." In 1974, he was appointed director of the Massachusetts Institute of Technology's Centre for Advanced Visual Studies, retiring in 1993. He died shortly after the opening of an exhibition of his work at Berlin's Neue Nationalgalerie and is survived by his wife and four children.