Versatile Geometric Flow Visualization by Controllable Shape and Volumetric Appearance

Abstract

We present a novel visualization technique for geometry-based visualization of vector fields. Our approach generalizes and combines several existing approaches in a flexible framework using a scalable GPU-accelerated implementation. We map characteristic lines to a variety of glyphs. The user can define multiple cross-sectional shapes that will be used for extrusion. Our system interpolates between these shapes as requested, either based on attributes of the vector field and the characteristic lines or using global user-controlled parameters. Thus, a single characteristic line can use different cross-sectional shapes in different parts to aid the visualization of different phenomena. Transitions can be smooth or discrete and we support highlighting of silhouettes. Additionally, we track and visualize the rotation in the vector field and offer full control of the color mapping, the opacity and the radii along the characteristic lines. Texture-based approaches such as 3D line integral convolution (3D LIC) offer another avenue to vector field visualization. In 3D, they typically rely on sparsely placed seed points. We emulate their appearance with our geometry-based approach through an approximation of the volume integral within our glyphs. Combined with fast order-independent transparency, our GPU implementation achieves fast rendering, even at high resolutions, while keeping the memory footprint moderate.