Sketch-based CNC

Jennifer Jacobs

Most digital fabrication workflows impose a strong separation between design and fabrication. Designs are first modeled in computer aided design software, and when completed, converted to tool-paths which are uploaded to control software and autonomously executed by the fabrication machine. While there are advantages to this highly structured workflow, it restricts the ability for improvisation and revision. In addition, it eliminates the opportunity for embodied forms of expression, and direct engagement with the material during the fabrication process.

I explored ways of supporting exploratory, intuitive, and immediate design practices in digital fabrication by creating a system for interactive control of a three-axis Computer Numerical Control (CNC) machine. I circumvented the traditional control interface of a large-format ShopBot machine to enable direct control by a human operator. I developed a tablet-based interface where people could draw designs with a pressure sensitive stylus. Each stroke a person drew was executed by the machine as it was completed. I also developed a custom drawing tool that fit into the ShopBot spindle and enabled the designer to switch between two different colors of acrylic paint as they drew. The tool mechanism was wireless, and was driven by two servomotors controlled through a bluetooth-enabled microcontroller.

The complete system was made available to the general public during a four-day installation which enabled people to interact with the machine. In the process, I observed how the drawing-based interface lowered barriers to entry for digital fabrication and enabled people to execute organic and gestural forms and patterns with the machine. This work is part of ongoing research to explore ways of modifying existing digital fabrication machines to support embodied and intuitive forms of design and making.