Raycasting vector fields

Direct Volume Rendering (DVR) allows the holistic visualization of huge volumetric data sets in a single image. Computational fluid dynamics data is in principle well suited for DVR. But efficient mappings of the directional information of vector fields are still to be found. We investigate how the raycasting technique can be used to directly render vector fields. Our approach is based on the perception that other flow visualization techniques use visualization objects that are locally tangential to the vector field together with directed light sources. From this, we developed the idea to shade streamlines at sampling points when raycasting a vector field. We extended this approach further to more abstract mappings where pseudo color is used. Combining opacity mapping, pseudo color mapping, and streamline shading we can express flow speed and flow direction together in one single image.