Roudaut A., Karnik A., Löchtefeld M. and Subramanian S. (CHI’13)




To appear at CHI13


We introduce the term shape resolution, which adds to the existing definitions of screen and touch resolution. We propose a framework, based on a geometric model (Non- Uniform Rational B-splines), which defines a metric for shape resolution in ten features. We illustrate it by comparing the current related work of shape changing devices. We then propose the concept of Morphees that are self-actuated flexible mobile devices adapting their shapes on their own to the context of use in order to offer better affordances. For instance, when a game is launched, the mobile device morphs into a console-like shape by curling two opposite edges to be better grasped with two hands. We then create preliminary prototypes of Morphees in order to explore six different building strategies using advanced shape changing materials (dielectric electro active polymers and shape memory alloys). By comparing the shape resolution of our prototypes, we generate insights to help designers toward creating high shape resolution Morphees.

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Shape resolution

Our definition of shape resolution is based on the model of Non-Uniform Rational B-splines (NURBS) and has ten features (illustrated on this figure) that are analogous to the ones used for display resolution such as number of pixel, size of pixel, bit per pixel etc. However, a high resolution feature is not about maximizing its value but maximizing the range of its possible values. For instance, a shape has a high- curvature resolution if its surface has range of curvatures comprised between -π and π (concave to convex spike).



A Morphee is a self-actuated flexible mobile device that address the multiple affordance desired by any applications and transform itself into desired shapes. We envision that app stores can potentially evolve to give opportunities to developers to create practical applications with their specific form factors. We compare six actuation strategies of Morphees, five using advanced technologies in morphing materials: Dielectric Electro Active Polymers (DEAP) and Shape Memory Alloys (SMA).