Shape retaining chain linked model for real-time volume haptic rendering

Haptic rendering is the process of computing and generating forces in response to user interactions with virtual objects. While we speak of real-time volume rendering for visualization, we are still very much limited to Surface models for manipulation due to overwhelming computational requirements for volumetric models. In this paper, we propose a new volumetric deformable model that is suitable for volume haptic interactions. The volume elements of our proposed model are linked to their nearest neighbors and their displacements are transformed into potential energy of the virtual object. The original 3D ChainMail algorithm does not account the fact that the residual energy left in the object after some interactions becomes a critical problem in haptic rendering. We present the shape-retaining chain linked model, which allows for fast and realistic deformation of elastic objects. Furthermore, we incorporate force-voltage analogy (duality) concepts into the proposed shape-retaining chain linked representation in order to develop a fast volumetric haptic model that is Suitable for realtime applications. We experimented with homogenous and non-homogenous virtual objects of size 75×75×75 volume elements, and we were able to verify real-time and realistic haptic interaction with a 3DOF PHANToM™ haptic device.