I recently wrote an interesting little GLSL shader program for a course at my university. I was given the topic Non-Photorealistic Fiber Rendering. What we call ‘Fibers’ are the nerve pathways that go through the human brain. There are quite many of them, and the goal is not to harm them while performing a tumor resection, for example. Otherwise functional areas of your brain (speaking, walking, etc.) might not be functional anymore after surgery. Since you cannot see the fibers (or bundles thereof) when you open up the head and look at the brain, it is important to visualize them. I did that using an approach that does not aim to provide realism, but comprehensibility (akin to the schematic drawings or similar illustrations found in medical books).
So my task was to implement an approach for halo rendering introduced by Everts et al. I combined it with another approach to depict contours from Otten et al. The result was quite nice already. To get an even better impression of spatial depth relationships, I had the idea of adding a modified approach to ambient occlusion to my program. I am pretty satisfied with the results:
Without Ambient Occlusion, following the combined Everts & Otten approach (click to enlarge):
With added Ambient Occlusion (click to enlarge):
Obviously this just focuses on the rendering of the fibers. Surrounding anatomy like brain tissue or potential tumors are not depicted. What you see is a set of fibers that ‘connects’ your eyes to your brain.
The tool shown there works on OSX, Ubuntu and Windows using the MeVisLab framework. The framework also allows Python scripting.