A tetrahedra-based stream surface algorithm

IEEE Trans. Visual. Comput. Graphics

Hamann

et al. 2010

Fig. 1. A path surface generated from a turbulent jet dataset, rendered in two different styles using the framework proposed in this paper. In the left image, the surface is opaque, and the front and back side are rendered with yellow and blue, respectively. An adaptive stripe pattern visualizes individual pathlines on the surface and provides the orientation of the flow. On the right, the surface is rendered transparently with a denser stripes to give a hatching-like appearance. Both figures emphasize surface silhouettes for better distinction of individual surface layers.Abstract-Integral surfaces are ideal tools to illustrate vector fields and fluid flow structures. However, these surfaces can be visually complex and exhibit difficult geometric properties, owing to strong stretching, shearing and folding of the flow from which they are derived. Many techniques for non-photorealistic rendering have been presented previously. It is, however, unclear how these techniques can be applied to integral surfaces. In this paper, we examine how transparency and texturing techniques can be used with integral surfaces to convey both shape and directional information. We present a rendering pipeline that combines these techniques aimed at faithfully and accurately representing integral surfaces while improving visualization insight. The presented pipeline is implemented directly on the GPU, providing real-time interaction for all rendering modes, and does not require expensive preprocessing of integral surfaces after computation.

Section: Integral Surface Generationmentioning

confidence: 99%

IRIS: Illustrative Rendering for Integral Surfaces

Hummel

IEEE Trans. Visual. Comput. Graphics

Hamann

et al. 2010

“…For the case of tetrahedral grids, Scheuermann et al [15] exploited the existence of an analytic flow solution for tetrahedral grids endowed with linear interpolation to compute a stream surface on a per-tetrahedron basis. Due to the linear nature of the vector field inside every grid cell, streamline paths are available in closed form.…”

Section: An Overview Of Computation Techniquesmentioning

confidence: 99%

Generation of Accurate Integral Surfaces in Time-Dependent Vector Fields

IEEE Trans. Visual. Comput. Graphics

Krishnan

Tricoche

et al. 2008

Abstract-We present a novel approach for the direct computation of integral surfaces in general vector fields. As opposed to previous work, which we analyze in detail, our approach is based on a separation of integral surface computation into two stages: surface approximation and generation of a graphical representation. This allows us to overcome several limitations of previous techniques. We first describe an algorithm for surface integration that approximates a series of timelines using iterative refinement and computes a skeleton of the integral surface. In a second step, we generate a well-conditioned triangulation. The presented approach allows a highly accurate treatment of very large time-varying vector fields in an efficient, streaming fashion. We examine the properties of the presented methods on several example datasets and perform a numerical study of its correctness and accuracy. Finally, we examine some visualization aspects of integral surfaces.

“…van Wijk [27] gave a global approach that implicitly represents stream surfaces as implicit surfaces in an advected scalar field. Scheuermann et al [21] exploited the existence of an analytic flow solution for tetrahedral grids with linear interpolation to propagate a stream surface through tetrahedra basis. While these techniques are conceptually elegant, the restrictions introduced with respect to choice of starting curve or surface resolution severely limit the flexibility of stream surfaces for vector field visualization purposes.…”

Section: Stream Surface Definition and Computationmentioning

confidence: 99%

Parallel stream surface computation for large data sets

Camp

Childs

IEEE Symposium on Large Data Analysis and Visualization (LDAV)

et al. 2012

Figure 1: Stream surfaces generated during this study. On the left, flow around an ellipsoid. In the middle, flow in a tokamak. On the right, flow from a thermal hydraulics simulation. ABSTRACTParallel stream surface calculation, while highly related to other particle advection-based techniques such as streamlines, has its own unique characteristics that merit independent study. Specifically, stream surfaces require new integral curves to be added continuously during execution to ensure surface quality and accuracy; performance can be improved by specifically accounting for these additional particles. We present an algorithm for generating stream surfaces in a distributed-memory parallel setting. The algorithm incorporates multiple schemes for parallelizing particle advection and we study which schemes work best. Further, we explore speculative calculation and how it can improve overall performance. In total, this study informs the efficient calculation of stream surfaces in parallel for large data sets, based on existing integral curve functionality.