StepDance: A Toolkit for Redesigning CNC Machines Using Physical Metaphors

Researchers can build craft-aligned digital fabrication technologies by designing interfaces inspired by craft tools. This process often demands real-time physical interactions not supported by today’s automation-focused CNC control systems. We theorize we can lower engineering challenges for craft-aligned CNC prototyping by allowing designers to modify existing CNCs to support both automated and real-time control. We contribute a new creative motion control system, Stepdance, which consists of two elements: 1) modular controllers that replace the G-code controller of a CNC and can be chained together to develop new interfaces, and 2) a modular programming library that supports declarative mappings between live user input, pre-programmed operations, and machine motion. We developed Stepdance with practitioners at the Haystack Mountain School of Craft, where we used the system to modify commercial plotters and 3D printers. We analyze the resulting artifacts, interactions, and ideas to discuss how Stepdance can broaden the practice of CNC design via physical metaphor.