Previous reviews describe interfaces that can deform and shape change through the term shape-changing interfaces. However, this term implies that interfaces have to be self-actuated, should emphasize output (mostly in terms of physical reconfiguration and movement), and exclude non-display or input-only interfaces. On the contrary, we aim to emphasize the main characteristic of deformable interfaces which are: user input and user-controlled deformation.
We define Deformable Interfaces as:
1. Made entirely or in part (especially their surface) of soft and malleable materials, including fabric, rubber, and clay
2. Emphasizing physical input and user-controlled deformations over self-actuation and shape change
3. Supporting user input through deformable materials, even when combining rigid and deformable parts, or when actuated
4. Allowing users to input with gestures that are unlikely or impossible with rigid interfaces (e.g., twist, bend, stretch)