KAMU kanazawa TOWN hack “bench bench bench” アートベンチ

The benches were installed at four locations around the city. The logs are finished with a urethane coating for outdoor sculpture, and the bases are painted gray.

Logs were 3D-scanned with their natural form intact, analyzed digitally, and then shaped by an industrial robotic arm fitted with a chainsaw. This is an early application of a new manufacturing system that can machine large-diameter timber from any angle, something conventional machines that hold the material inside them cannot do. The bases are made of structural plywood.

Before fabrication, chainsaw cuts and deep cuts into inside corners were tested, and the blade and jig were revised. Each log was machined in two stages, a roughing pass followed by a finishing pass, and then finished by hand. Machining time varied greatly with the form; one bench took about 23 hours including CAM.

Each of the five benches was developed from a different log, so each differs in size and form.

Early studies explored shaping the benches from Styrofoam and urethane, but the approach was switched to machining logs directly with a chainsaw mounted on a robotic arm. The scanned logs were converted into low-poly models, and the meshes were edited into polyhedral forms while securing as much seating surface as possible. The basic rule was to carve the top into facets and leave the underside as raw log, while the fifth bench was designed as a form distinct from the other four.