4.1 Basic Idea

The goal of volume rendering is to create a two dimensional image from sampled three dimensional values; like an X-ray scanner that creates two dimensional picture of the inside of the human body from three dimensional data. The idea behind volume rendering is similar to X-ray technique. Rays are passed through the volume accumulating the effects of density to give the final two dimensional image. The amount of density taken into account along the ray depends of the classification process that determines which components are made transparent and which are opaque. The goal is to transform a set of samples in three dimensions to a meaningful two dimensional image where features of interest can be easily seen.