Haptic Rendering: Point- and Ray-Based Interactions

In this paper, we summarize our progress on two interaction techniques (point-based and ray-based) for haptic rendering. First, we describe a new point-based rendering technique that is computationally less expensive than previously proposed methods. We use a localized search procedure to reduce the number of computations and make it independent of the number polygons of the polyhedron. Second, we discuss the implementation details of a ray-based technique together with its advantages. We have utilized this rendering technique to display the haptic interactions between 3D objects and the stylus modeled as a line segment. In order to develop more effective multimodal VEs, we have experimented with multi-threading (on Windows NT platform) and multi-processing (on UNIX platform) techniques and have successfully separated the visual and haptic servo loops. Our experience is that both techniques are quite useful in achieving high haptic rendering rates and stable haptic interactions. Althou..