Working in three dimensions rather than two is a new challenge when it comes to creating visual art—in fact, the choice to do so transforms an artist’s work into something more than visual and hurls it into the realm of the tactile. It also adds an additional category of attributes to a piece: is it heavy? Is it sharp? Is it fragile?

The answers to such questions involve raw, almost emotional qualities, conveyed much more quickly than they can be in a two-dimensional work.

Metal sculpture may be the zenith of such touch-evocative three-dimensional art, smooth and cold as polished forged steel or jagged and rusty like old nautical equipment. Holyoke-based artists Julian Halpern and Michael Martindell have, between the two of them, manipulated the medium for decades, having begun welding together in the Afro-American Studies department at UMass in 1992. Many of their materials and ideas are collected from the post-industrial environments they’ve inhabited since embracing the art, and many come from the old Mountain Park site on Mount Tom.

Recent work by the sculptors is on view through the third week of July at Open Square’s 4th Floor Gallery in an exhibit that juxtaposes some of the rougher, less refined charm of found objects with the sleek and shiny look of welded steel, mating the multihued with the monochrome and precision with randomness.

Through July 24, Open Square 4th Floor Gallery, 4 Open Square Way, Holyoke, (413) 532-5057, www.opensquare.com.