What's That Shape? Investigating Eyes-Free Recognition of Textile Icons

Textile surfaces, such as on sofas, cushions, and clothes, offer promising alternative locations to place controls for digital devices. Textiles are a natural, even abundant part of living spaces, and support unobtrusive input. While there is solid work on technical implementations of textile interfaces, there is little guidance regarding their design-especially their haptic cues, which are essential for eyes-free use. In particular, icons easily communicate information visually in a compact fashion, but it is unclear how to adapt them to the haptics-centric textile interface experience. Therefore, we investigated the recognizability of 84 haptic icons on fabrics. Each combines a shape, height profile (raised, recessed, or fat), and affected area (filled or outline). Our participants clearly preferred raised icons, and identified them with the highest accuracy and at competitive speeds. We also provide insights into icons that look very different, but are hard to distinguish via touch alone.