Illuminated lines revisited

Abstract

For the rendering of vector and tensor fields, several texturebased volumetric rendering methods were presented in recent years. While they have indisputable merits, the classical vertex-based rendering of integral curves has the advantage of better zooming capabilities as it is not bound to a fixed resolution. It has been shown that lighting can improve spatial perception of lines significantly, especially if lines appear in bundles. Although OpenGL does not directly support lighting of lines, fast rendering of illuminated lines can be achieved by using basic texture mapping. This existing technique is based on a maximum principle which gives a good approximation of specular reflection. Diffuse reflection however is essentially limited to bidirectional lights at infinity. We show how the realism can be further increased by improving diffuse reflection. We present simplified expressions for the Phong/Blinn lighting of infinitesimally thin cylindrical tubes. Based on these, we propose a fast rendering technique with diffuse and specular reflection for orthographic and perspective views and for multiple local and infinite lights. The method requires commonly available programmable vertex and fragment shaders and only two-dimensional lookup textures.

PathlinesExplorer - Image-based exploration of large-scale pathline fields

“…Also, another enhancement could be done by using an algorithm that investigates the optimal viewpoints, which can uniquely illustrates the flow field and have minimal average depth layers size (number of linked list elements). Moreover, enhance the quality of the rendered lines by applying some shading techniques as the o;[ne presented by Malloet al [7] or LineAO method by Eichelbaum et al [3]. Also, combine our work with other optimization methods for lines selection, namely, Opacity Optimization method provided by Gnther et al [5].…”

Parallel hierarchical visualization of large time-varying 3D vector fields

“…We utilized illuminated lines [14] to render the glyphs, which not only accelerates the rendering, but also achieves more pleasing 3D effects. Figure 13 shows the rendering results of the solar plume data set.…”

View-Dependent Streamlines for 3D Vector Fields

“…A number of enhancements have also been done for streamline rendering quality, for example by Mallo et al [16]. Salzbrunn et al [22] introduce the concept of streamline predicates which allows differentiating streamlines based on user queries.…”