Comparison of Algorithms for Haptic Interaction With Isosurfaces Extracted From Volumetric Datasets.

Combinations of graphics and haptics libraries are used in medical simulations for simultaneous visualization and tactile interaction with complex 3D anatomy models. The minimum frame rate of 1 kHz for haptics rendering makes it a nontrivial problem when dealing with complex and highly detailed polygonal models. Multiple haptics algorithms based on polygonal mesh rendering, volume haptics, and intermediate representation are evaluated in terms of their servoloop rendering time, client thread rendering time, and quality of force feedback. Algorithms include OpenHaptics' Feedback Buffer and Depth Buffer, GodObject and Ruspini renderers in h3d, chai3d implementation in h3d, ScalarSurfaceFriction mode in Volume Haptics ToolKit (vhtk), and the authors' intermediate representation algorithm based on volumetric data. The latter, in combination with surface graphics visualization, is found to deliver the best rendering time, to detect all collisions and to provide correct haptic feedback where other algorithms fail.