Comparing Fabrication Workflows in CAD to Support Design Reasoning

When novices fabricate, they start by choosing a workflow (e.g., laser cutting, 3D printing, etc.) and corresponding software from a narrow set they know. As they advance their design, another workflow might better suit their intent, but their models remain committed to the original workflow. This prohibits exploration, which fosters informed decision-making. In this paper, we investigate how CAD interfaces can guide exploration and comparison of workflows. Specifically, comparison can advance users' reasoning about design decisions. We developed a prototype interface, CAMeleon, which lets users compare fabrication workflows. Users load 3D models and preview outcomes from different workflows. We hypothesize that presenting alternative outcomes supports exploration and scaffolds informed decision-making. Upon workflow confirmation, CAMeleon allows users export both machine and human instructions for the chosen fabrication workflow. We interviewed seven fabrication educators to understand how such tools can be integrated into teaching and to demonstrate how we adjust our tool based on their insights. In user evaluation (N = 12), guided comparison helped participants consider a broader range of workflows, reflect on trade-offs, and experiment with new ways of planning.