Dennis Oppenheim, 72, conceptual artist and sculptor

He was 72.

Belonging to a generation of artists who saw portable painting and sculpture as obsolete, Mr. Oppenheim started out in the realm of the esoteric, the immaterial, and the chronically unsalable.

But he was always a showman, not averse to the circuslike, or to courting danger.

For “Rocked Circle — Fear,’’ a 1971 body art piece, he stood at the center of a 5-foot-wide circle painted on a New York sidewalk while a friend dropped fist-size stones from three stories above, aiming for inside the circle without hitting the artist. There were no mishaps.

Mr. Oppenheim had a penchant for grandiosity. It was implicit in the close-up photograph of a splinter in his finger, portentously titled “Material Interchange.’’ It was explicit in “Charmed Journey Through a Step-Down Transformer,’’ a Rube Goldberg-like outdoor installation from 1980 that sprawled 125 feet down a slope at the Wave Hill garden and cultural center in the Bronx, its disparate parts suggesting engines, tracks, organ pipes, and much else.

Sculptures like these, from Mr. Oppenheim’s Factories series, combined aspects of machines and industrial architecture with intimations of mysterious human processes, presenting what he called “a parallel to the mental processing of a raw idea’’ by both artist and viewer.

Many works involved moving parts, casts of animals (whole or partial); upturned or tilted building silhouettes; and sound, water, and fireworks, which on occasion prompted unscheduled visits by the Fire Department.

Several of his sculptures used enlarged objects in the manner of Pop Art: orange safety cones, Hershey’s Kisses, diamond rings, an easy chair, or paintbrushes. “Device to Root Out Evil’’ (1997) is an inverted church, its steeple provocatively stuck in the ground.

Dennis Allan Oppenheim was born in Electric City, Wash.