An Improved Ray Tracing Method for Volume Rendering

A 3D hybrid scene is composed of polygonal models as well as semi-transparent volumetric objects. The polygonal models are represented by using triangular meshes while the volumetric objects are constructed by using voxels of different densities. Since conventional ray tracing techniques are infeasible to shade the hybrid scene, a specialized raytracing algorithm is proposed to render it. First, we design a new method to compute ray paths inside the volumetric objects based on the principles of geometric optics. Secondly, we derived an illumination model dedicated to calculate lighting effects of the volumetric objects. As a result, the proposed ray-tracing algorithm is capable of rendering not only the polygonal models but also the semi-transparent volumetric objects.