Preparing Spatial Haptics for Interaction Design

Spatial haptics is a fascinating technology with which users can explore and modify 3D computer graphics objects with the sense of touch, but its application potential is often misunderstood. For a large group of application designers it is still unknown, and those who are aware of it often have either too high expectations of what is technically achievable or believe it is too complicated to consider at all. In addition, spatial haptics is in its current form ill-suited to interaction design. This is partly because the properties and use qualities cannot be experienced in an application prototype until a system is fully implemented, which takes too much effort to be practical in most design settings. In order to find a good match between a solution and a framing of a problem, the designer needs to be able to mould/shape/form the technology into a solution, but also to re-frame the problem and question initial conceptual designs as she learns more about what the technology affords. Both of these activities require a good understanding of the design opportunities of this technology. In this thesis I present a new way of working with spatial haptic interaction design. Studying the serially linked mechanism from a well-known haptic device, and a forcereflecting carving algorithm in particular, I show how to turn these technologies from an esoteric engineering form into a form ready for interaction design. The work is grounded in a real application: an oral surgery simulator named Kobra that has been developed over the course of seven years within our research group. Its design has gone through an evolutionary process with iterative design and hundreds of encounters with the audience; surgeon-teachers as users and potential customers. Some ideas, e.g. gestalting authentic patient cases, have as a result received increased attention by the design team, while other ideas, e.g. automatic assessment, have faded away. Simulation is an idea that leads to ideals of realism; that e.g. simulated instruments should behave as in reality, e.g. a simulated dental instrument for prying teeth is expected to behave according to the laws of physics and give force and torque feedback. If it does not, it is a bad simulation. In the present work it is shown how some of the realism ideal is unnecessary for creating meaningful learning applications and can actually even be counter-productive, since it may limit the exploration of creative design solutions. This result is a shift in perspective from working towards constantly improving technological components, to finding and making use of the qualities of modern, but not necessarily absolute cutting-edge, haptic technology. To be able to work creatively with a haptic system as a design resource we need to learn its material qualities and how through changing essential properties meaningful experiential qualities can be modulated and tuned. This requires novel tools and workflows that enable designers to explore the creative design space, create interaction sketches and tune the design to cater for the user experience. In essence, this thesis shows how one instance of spatial haptics can be turned from an esoteric technology into a design material, and how that can be used, and formed, with novel tools through the interaction design of a purposeful product in the domain of dental education.