Title :
Real-time Interactions and Synchronization of Voxel-based Collaborative Virtual Environments
Author :
Acosta, Eric ; Liu, Alan
Author_Institution :
National Capital Area Med. Simulation Center, Uniformed Services Univ., Bethesda, MD
Abstract :
Collaborative virtual environments (C-VE) facilitate team-oriented training on virtual reality-based surgical simulators. Many C-VEs replicate the VE on each user´s machine to allow for real-time interactions. However, this solution does not work well when modifying voxel-based C-VEs because large and frequent volumetric updates make it difficult to synchronize the C-VE. This paper describes a hybrid depth-buffered image (DBI) and geometry-based rendering method created to simulate visual interactions between local virtual bone cutting tools and remotely maintained volumetric bone material for a craniotomy simulator. For real-time interactions, users only store a DBI of the volumetric C-VE and composite it with rendered images of surgical tools. Additionally, we describe methods to combat network bandwidth/latency to remotely simulate haptic and bone drilling interactions between users´ tools and the volumetric VE. For haptic feedback, a multi-rate solution (Cavusoglu and Tendick, 2000) allows users to construct a local approximation of the volumetric C-VE to compute new forces. Only 2D DBI updates are required to synchronize different users when the bone changes due to drilling. Our approach provides an improved performance over a replicated VE that uses 3D model-based updates
Keywords :
groupware; haptic interfaces; medical computing; medical image processing; real-time systems; rendering (computer graphics); surgery; virtual reality; 3D model-based update; bone drilling interaction; craniotomy simulator; geometry-based rendering; haptic feedback; haptic interaction; hybrid depth-buffered image; real-time interaction; virtual bone cutting tool; virtual reality-based surgical simulator; visual interaction simulation; volumetric bone material; volumetric update; voxel-based collaborative virtual environment; Bones; Capacitance-voltage characteristics; Collaboration; Collaborative work; Drilling; Haptic interfaces; Rendering (computer graphics); Solid modeling; Surgery; Virtual environment;
Conference_Titel :
3D User Interfaces, 2007. 3DUI '07. IEEE Symposium on
Conference_Location :
Charlotte, NC
Print_ISBN :
1-4244-0907-1
DOI :
10.1109/3DUI.2007.340785