Hybrid visualization of asymmetric tensor fields : glyphs and hyperstreamlines

Asymmetric tensor fields are useful for understanding fluid flow and solid deformation. They present new challenges, however, for traditional tensor field visualization techniques such as hyperstreamline placement and glyph packing. This is because the physical behavior of tensors inside real domains where eigenvalues are real is fundamentally different from the behavior of tensors inside complex domains where eigenvalues are complex. I present a hybrid visualization approach in which hyperstreamlines are used to illustrate the tensors in the real domains and glyphs are employed in complex domains. This enables an effective visualization of the physical patterns everywhere and also provides a more intuitive illustration of elliptical patterns in the complex domains. In addition, I encode the tensor magnitude in the size of the glyphs and density of the hyperstreamlines. The visualization is applied to surfaces using an image space approach where the tensor field is projected to the image plane. This allows visual exploration of the data set from different viewpoints and at different resolutions. The effectiveness of this visualization technique is demonstrated through applications to complex simulated engine fluid flow and earthquake deformation data