Tandem: Reproducible Digital Fabrication Workflows as Multimodal Programs

Experimental digital fabrication workflows are increasingly common in human-computer interaction research, but are difficult to reproduce. We present Tandem, a software library that lets a fabricator implement an end-to-end fabrication workflow as a computational notebook program that others can run to physically reproduce the workflow. Tandem notebook programs read and write to CAD and CAM software, project augmented reality interfaces onto machines for manual interventions, and directly control fabrication machines. Fabricators can also denote potential mismatches between the physical and the digital as explicit assertions in code. Using two-sided CNC milling as an example, we demonstrate how to implement a complex workflow as a single program that can be re-run by others while supporting quality control and improving reproducibility.