Extracting Hand Grasp & Motion for Intent Expression in Mid-Air Shape Deformation: A Concrete & Iterative Exploration through a Virtual Pottery Application

by | Oct 25, 2015

Authors: Vinayak and Karthik Ramani
Computers & Graphics, Volume 55, April 2016, Pages 143-156, ISSN 0097-8493, (http://dx.doi.org/10.1016/j.cag.2015.10.012.)

We describe the iterative design and evaluation of a geometric interaction technique for bare-hand mid-air virtual pottery. We model the shaping of a pot as a gradual and progressive convergence of the pot-profile to the shape of the user’s hand represented as a point-cloud (PCL). Our pottery-inspired application served as a platform for systematically revealing how users use their hands to express the intent of deformation during a pot shaping process. Our approach involved three stages: (a) clutching by proximal-attraction, (b) shaping by proximal-attraction, and (c) shaping by grasp+motion. The design and implementation of each stage was informed by user evaluations of the previous stage. Our work evidently demonstrates that it is possible to enable users to express their intent for shape deformation without the need for a fixed set of gestures for clutching and deforming a shape. We found that the expressive capability of hand articulation can be effectively harnessed for controllable shaping by organizing the deformation process in broad classes of intended operations such as pulling, pushing, and fairing. After minimal practice with the pottery application, users could figure out their own strategy for reaching, grasping, and deforming the pot. Users particularly enjoyed using day-to-day physical objects as tools for shaping pots.





Vinayak received his Ph.D. in Mechanical Engineering from Purdue University in December 2015. The central theme of his research is the expression of design intent towards supporting early phase idea generation for product form exploration. During his Ph.D. at the C-Design Lab, he investigated symbolic and geometric interpretations of hand gestures, hand grasp, and arm movements for mid-air shape conceptualization. He extended these ideas to the tangible interactions for quick design ideation using hand-held mobile devices. Currently, he is a post-doctoral scholar in the School of Mechanical Engineering at Purdue University where he continues working at the C-Design Lab. His current research involves building systems for collaborative design using mobile technology.   Personal Webpage: https://sites.google.com/site/fvinayak1/