Streamarrows: Visualizing Multiple Layers of Stream- Surfaces

Occlusion is a crucial spatial cue for the human visual system. Painters as well as researchers in the eld of computer graphics have been dealing with this aspect for a long time. In the eld of visualization occlusion can be especially problematic. We present a new approach to dealing with streamsurfaces that occlude major parts of the system representation. Analyzing mixed-mode oscillations, which are a special class of analytically deened dynamical systems, we came across geometrically complex streamsurfaces with curly shape. Certain regions of these surfaces, that are necessary to describe the behavior of the system, occlude major parts of the model. We combined and adopted several visualization techniques to deal with this problem. Streamarrows, which are semi-transparent portions of the streamsurface, allow the viewer to see through and diminish the problem of occlusion. Cross-sections and the removal of certain portions of the model reduce occlusion as well and thus improve visual perception. Choosing the shape of an arrow for segmentation allows to visualize even more information at the streamsurface, e.g., the direction of the ow. An anisotropic spot noise texture is further used to emphasize ow within a streamsurface. Finally animation techniques were applied to facilitate the interpretation of dynamical systems with complex shaped streamsurfaces.