Shape-Kit: A Design Toolkit for Crafting On-Body Expressive Haptics

Driven by the vision of everyday haptics, the HCI community is advocating for "design touch first" and investigating "how to touch well." However, a gap remains between the exploratory nature of haptic design and technical reproducibility. We present Shape-Kit, a hybrid design toolkit embodying our "crafting haptics" metaphor, where hand touch is transduced into dynamic pin-based sensations that can be freely explored across the body. An ad-hoc tracking module captures and digitizes these patterns. Our study with 14 designers and artists demonstrates how Shape-Kit facilitates sensorial exploration for expressive haptic design. We analyze how designers collaboratively ideate, prototype, iterate, and compose touch experiences and show the subtlety and richness of touch that can be achieved through diverse crafting methods with Shape-Kit. Reflecting on the findings, our work contributes key insights into haptic toolkit design and touch design practices centered on the "crafting haptics" metaphor. We discuss in-depth how Shape-Kit's simplicity, though remaining constrained, enables focused crafting for deeper exploration, while its collaborative nature fosters shared sense-making of touch experiences.