This thesis presents implementation and evaluation of a multiple-points haptic rendering algorithm using the PHANToM haptic interface, in the context of our Virtual Haptic Back Project at Ohio University. This algorithm will increase realism in palpation with the Virtual Haptic Back and other virtual haptic palpation tasks when compared to the single point haptic rendering.
The single-point haptic rendering cannot provide tool-object interactions in which more than one object is in contact simultaneously at different locations of the tool or finger. Since a single point does not represent the finger haptically well, this thesis uses a multiple-points probe. The multiple-points collision detection is computationally expensive and complicated than the single-point haptic rendering. This thesis constructs the volume object using a sphere. The center of this sphere is the original PHANToM position and the end-points consist of points on the sphere. The collision detection between these line segments and objects in the virtual scene is completed and a resultant force is displayed to the user. The multiple-points haptic rendering algorithm was integrated with simple haptic objects and with the complex Virtual Haptic Back. The multiple-points algorithm is made efficient using concepts such as rasterisation, hashing and spatial decomposition.
Experiments have determined that multiple-points haptic rendering can improve the user’s experience with virtual reality applications based on this first step in implementation and evaluation.