Open Source Volume Rendering

Exposure Render is an open source  Direct Volume Rendering Application that is now available in an official version 1. It runs under Windows XP or later and needs a CUDA compatible GPU. You can download a compiled version ready to run or the full source code.

Volume rendering is particularly applicable to rendering medical scans or anything that returns data about the nature of a volume of space - usually as a set of 2D slices.  See Chapter 39 of GPU Gems for an overview of volume rendering. Color and opacity values are assigned to each point in space, lighting and a camera position is set up and then the scene is rendered usually via a clever ray tracing algorithm - direct volume rendering - or by constructing a mesh approximation. The big problem with direct volume rendering is that it is computationally expensive...