Driven by fast development of both virtual reality and volume visualization, we discuss some critical techniques towards building a volumetric VR system, specifically the modeling, rendering, and manipulations of a volumetric scene. Techniques such as voxel-based object simplification, accelerated volume rendering, fast stereo volume rendering, and volumetric “collision detection” are introduced and improved, with the idea of demonstrating the possibilities and potential benefits of incorporating volumetric models into VR systems.