Transforcers: Exploring Information Communication through Surface-based Force Interactions

In the physical world, the force required to interact with an object provides rich information about its material properties and intended use: some objects deform easily when force is applied (e.g. a pillow) while others resist our attempts (e.g. a spring). Recent advances in haptic technology support integrating force modalities into interactive surfaces, presenting novel ways to convey material properties and create engaging experiences. However, little is known about how people perceive and interpret surface-based force interactions. To address this, we designed the Transforcer, a device generating normal, shear, and rotational forces, and studied user perceptions in different scenarios. Our findings show that force is experienced as a multi-layered interaction: bodily perception grounds interpretation, material qualities convey intent and control, and meaningful interactions emerge when body, task, and system align. We contribute (i) a design space of surface-based force interactions; (ii) the design and implementation of the Transforcer; (iii) findings from a semi-structured interview study; and (iv) design recommendations.