DevLan/vispubs huggingface dataset:
Interactive visualization of aircraft and power generation engines
Authors: Lisa Sobierajski Avila, William J. Schroeder
Published at Vis, 1997

Presents a system for interactively visualizing large polygonal environments such as those produced by CAD systems during the design of aircraft and power generation engines. Our method combines view frustum culling with level-of-detail modeling to create a visualization system that supports part motion and has the ability to view arbitrary sets of data. To avoid long system start-up delays due to data loading, we have implemented our system using a dynamic loading strategy. This also allows us to interactively visualize more data than could fit in memory at one time.
Interactive volume rendering for virtual colonoscopy
Authors: Suya You, Lichan Hong, Ming Wan, Kittiboon Junyaprasert, Arie E. Kaufman, Shigeru Muraki, Yong Zhou 0001, Mark Wax, Zhengrong Liang
Published at Vis, 1997

3D virtual colonoscopy has recently been proposed as a non-invasive alternative procedure for the visualization of the human colon. Surface rendering is sufficient for implementing such a procedure to obtain an overview of the interior surface of the colon at interactive rendering speeds. Unfortunately, physicians can not use it to explore tissues beneath the surface to differentiate between benign and malignant structures. In this paper, we present a direct volume rendering approach based on perspective ray casting, as a supplement to the surface navigation. To accelerate the rendering speed, surface-assistant techniques are used to adapt the resampling rates by skipping the empty space inside the colon. In addition, a parallel version of the algorithm has been implemented on a shared-memory multiprocessing architecture. Experiments have been conducted on both simulation and patient data sets.
Interval volume tetrahedrization
Authors: Gregory M. Nielson, Junwon Sung
Published at Vis, 1997

The interval volume is a generalization of the isosurface commonly associated with the marching cubes algorithm. Based upon samples at the locations of a 3D rectilinear grid, the algorithm produces a triangular approximation to the surface defined by F(x,y,z)=c. The interval volume is defined by /spl alpha//spl les/F(x,y,z)/spl les//spl beta/. The authors describe an algorithm for computing a tetrahedrization of a polyhedral approximation to the interval volume.
Isosurface extraction using particle systems
Authors: Patricia Crossno, Edward Angel
Published at Vis, 1997

Presents a new approach to isosurface extraction from volume data using particle systems. Particle behavior is dynamic and can be based on laws of physics or artificial rules. For isosurface extraction, we program particles to be attracted towards a specific surface value while simultaneously repelling adjacent particles. The repulsive forces are based on the curvature of the surface at that location. A birth-death process results in a denser concentration of particles in areas of high curvature and sparser populations in areas of lower curvature. The overall level of detail is controlled through a scaling factor that increases or decreases the repulsive forces of the particles. Once particles reach equilibrium, their locations are used as vertices in generating a triangular mesh of the surface. The advantages of our approach include: vertex densities are based on surface features rather than on the sampling rate of the volume; a single scaling factor simplifies level-of-detail control; and meshing is efficient because it uses neighbor information that has already been generated during the force calculations.
Multiresolution compression and reconstruction
Authors: Oliver G. Staadt, Markus H. Gross, Roger Weber
Published at Vis, 1997

The paper presents a framework for multiresolution compression and geometric reconstruction of arbitrarily dimensioned data designed for distributed applications. Although being restricted to uniform sampled data, the versatile approach enables the handling of a large variety of real world elements. Examples include nonparametric, parametric and implicit lines, surfaces or volumes, all of which are common to large scale data sets. The framework is based on two fundamental steps: compression is carried out by a remote server and generates a bit-stream transmitted over the underlying network. Geometric reconstruction is performed by the local client and renders a piecewise linear approximation of the data. More precisely, the compression scheme consists of a newly developed pipeline starting from an initial B-spline wavelet precoding. The fundamental properties of wavelets allow progressive transmission and interactive control of the compression gain by means of global and local oracles. In particular the authors discuss the problem of oracles in semiorthogonal settings and propose sophisticated oracles to remove unimportant coefficients. In addition, geometric constraints such as boundary lines can be compressed in a lossless manner and are incorporated into the resulting bit-stream. The reconstruction pipeline performs a piecewise adaptive linear approximation of data using a fast and easy to use point removal strategy which works with any subsequent triangulation technique.
Multiresolution tetrahedral framework for visualizing regular volume data
Authors: Yong Zhou 0001, Baoquan Chen, Arie E. Kaufman
Published at Vis, 1997

The authors present a multiresolution framework, called Multi-Tetra framework, that approximates volume data with different levels-of-detail tetrahedra. The framework is generated through a recursive subdivision of the volume data and is represented by binary trees. Instead of using a certain level of the Multi-Tetra framework for approximation, an error-based model (EBM) is generated by recursively fusing a sequence of tetrahedra from different levels of the Multi-Tetra framework. The EBM significantly reduces the number of voxels required to model an object, while preserving the original topology. The approach provides continuous distribution of rendered intensity or generated isosurfaces along boundaries of different levels-of-detail thus solving the crack problem. The model supports typical rendering approaches, such as marching cubes, direct volume projection, and splatting. Experimental results demonstrate the strengths of the approach.
Multivariate visualization using metric scaling
Authors: Pak Chung Wong, R. Daniel Bergeron
Published at Vis, 1997

The authors present an efficient visualization approach to support multivariate data exploration through a simple but effective low dimensional data overview based on metric scaling. A multivariate dataset is first transformed into a set of dissimilarities between all pairs of data records. A graph configuration algorithm based on principal components is then wed to determine the display coordinates of the data records in the low dimensional data overview. This overview provides a graphical summary of the multivariate data with reduced data dimensions, reduced data size, and additional data semantics. It can be used to enhance multidimensional data brushing, or to arrange the layout of other conventional multivariate visualization techniques. Real life data is used to demonstrate the approach.
Optimized geometry compression for real-time rendering
Authors: Mike M. Chow
Published at Vis, 1997

Most existing visualization applications use 3D geometry as their basic rendering primitive. As users demand more complex data sets, the memory requirements for retrieving and storing large 3D models are becoming excessive. In addition, the current 3D rendering hardware is facing a large memory bus bandwidth bottleneck at the processor to graphics pipeline interface. Rendering 1 million triangles with 24 bytes per triangle at 30 Hz requires as much as 720 MB/sec memory bus bandwidth. This transfer rate is well beyond the current low-cost graphics systems. A solution is to compress the static 3D geometry as an off-line pre-process. Then, only the compressed geometry needs to be stored in main memory and sent down to the graphics pipeline for real-time decompression and rendering. The author presents several new techniques for compression of 3D geometry that produce 2 to 3 times better compression ratios than existing methods. They first introduce several algorithms for the efficient encoding of the original geometry as generalized triangle meshes. This encoding allows most of the mesh vertices to be reused when forming new triangles. Their second contribution allows various parts of a geometric model to be compressed with different precision depending on the level of details present. Together, the meshifying algorithms and the variable compression method achieve compression ratios of 30 and 37 to one over ASCII encoded formats and 10 and 15 to one over binary encoded triangle strips. The experimental results show a dramatically lowered memory bandwidth required for real-time visualization of complex data sets.
Pearls found on the way to the ideal interface for scanned probe microscopes
Authors: Russell M. Taylor II, Jun Chen, Shoji Okimoto, Noel Llopis-Artime, Vernon L. Chi, Frederick P. Brooks Jr., Michael R. Falvo, Scott Paulson, Pichet Thiansathaporn, David Glick, Sean Washburn, Richard Superfine
Published at Vis, 1997

Since 1991, our team of computer scientists, chemists and physicists have worked together to develop an advanced, virtual-environment interface to scanned-probe microscopes. The interface has provided insights and useful capabilities well beyond those of the traditional interface. This paper lists the particular visualization and control techniques that have enabled actual scientific discovery, including specific examples of insight gained using each technique. This information can help scientists determine which features are likely to be useful in their particular application, and which would be just sugar coating. It can also guide computer scientists to suggest the appropriate type of interface to help solve a particular problem. We have found benefit in advanced rendering with natural viewpoint control (but not always), from semi-automatic control techniques, from force feedback during manipulation, and from storing/replaying data for an entire experiment. These benefits come when the system is well-integrated into the existing tool and allows export of the data to standard visualization packages.
Perceptual Measures For Effective Visualizations
Authors: Holly E. Rushmeier, Harrison H. Barrett, Penny Rheingans, Samuel P. Uselton, Andrew Watson
Published at Vis, 1997

How do we measure the effectiveness of visualizations? Clearly any metric has to be based on perceptual models, since we are measuring how a display is perceived and interpreted by a human being, Can we build useful metrics to evaluate the value of image content? Can we build metrics for user interaction that can feed back into our visualization systems to improve their effectiveness? Is it impossible to have real metrics for visualization? Are rules of thumb all we have? Can better rules be developed for effectiveness? We will consider imagery used both for photorealistic visualization and scientific visualization. Metrics for static images and dynamic displays will be discussed. The goal of this panel is to promote discussion of research or development that is neededfor improving the measurement of visualization effectiveness. We also hope to promote debate on whether general measurements are possible, or whether all visualization is case specific.
Principal stream surfaces
Authors: Wenli Cai, Pheng-Ann Heng
Published at Vis, 1997

The use of stream surfaces and streamlines is well established in vector visualization. However, the proper placement of starting points is critical for these constructs to clearly illustrate the flow topology. In this paper, we present the principal stream surface algorithm, which automatically generates stream surfaces that properly depict the topology of an irrotational flow. For each velocity point in the fluid field, we construct the normal to the principal stream surface through the point. The set of all such normal vectors is used to construct the principal stream function, which is a scalar field describing the direction of velocity in the fluid field. Volume rendering can then be used to visualize the principal stream function, which is directly related to the flow topology. Thus, topology in a fluid field can be easily modeled and rendered.
Repairing CAD models
Authors: Gill Barequet, Subodh Kumar 0001
Published at Vis, 1997

We describe an algorithm for repairing polyhedral CAD models that have errors in their B-REP. Errors like cracks, degeneracies, duplication, holes and overlaps are usually introduced in solid models due to imprecise arithmetic, model transformations, designer errors, programming bugs, etc. Such errors often hamper further processing such as finite element analysis, radiosity computation and rapid prototyping. Our fault-repair algorithm converts an unordered collection of polygons to a shared-vertex representation to help eliminate errors. This is done by choosing, for each polygon edge, the most appropriate edge to unify it with. The two edges are then geometrically merged into one, by moving vertices. At the end of this process, each polygon edge is either coincident with another or is a boundary edge for a polygonal hole or a dangling wall and may be appropriately repaired. Finally, in order to allow user-inspection of the automatic corrections, we produce a visualization of the repair and let the user mark the corrections that conflict with the original design intent. A second iteration of the correction algorithm then produces a repair that is commensurate with the intent. This, by involving the users in a feedback loop, we are able to refine the correction to their satisfaction.
ROAMing terrain: Real-time Optimally Adapting Meshes
Authors: Mark A. Duchaineau, Murray Wolinsky, David E. Sigeti, Mark C. Miller, Charles Aldrich, Mark B. Mineev-Weinstein
Published at Vis, 1997

Terrain visualization is a difficult problem for applications requiring accurate images of large datasets at high frame rates, such as flight simulation and ground-based aircraft testing using synthetic sensor simulation. On current graphics hardware, the problem is to maintain dynamic, view-dependent triangle meshes and texture maps that produce good images at the required frame rate. We present an algorithm for constructing triangle meshes that optimizes flexible view-dependent error metrics, produces guaranteed error bounds, achieves specified triangle counts directly and uses frame-to-frame coherence to operate at high frame rates for thousands of triangles per frame. Our method, dubbed Real-time Optimally Adapting Meshes (ROAM), uses two priority queues to drive split and merge operations that maintain continuous triangulations built from pre-processed bintree triangles. We introduce two additional performance optimizations: incremental triangle stripping and priority-computation deferral lists. ROAM's execution time is proportional to the number of triangle changes per frame, which is typically a few percent of the output mesh size; hence ROAM's performance is insensitive to the resolution and extent of the input terrain. Dynamic terrain and simple vertex morphing are supported.
Simplifying polygonal models using successive mappings
Authors: Jonathan D. Cohen 0001, Dinesh Manocha, Marc Olano
Published at Vis, 1997

We present the use of mapping functions to automatically generate levels of detail with known error bounds for polygonal models. We develop a piece-wise linear mapping function for each simplification operation and use this function to measure deviation of the new surface from both the previous level of detail and from the original surface. In addition, we use the mapping function to compute appropriate texture coordinates if the original map has texture coordinates at its vertices. Our overall algorithm uses edge collapse operations. We present rigorous procedures for the generation of local planar projections as well as for the selection of a new vertex position for the edge collapse operation. As compared to earlier methods, our algorithm is able to compute tight error bounds on surface deviation and produce an entire continuum of levels of detail with mappings between them. We demonstrate the effectiveness of our algorithm on several models: a Ford Bronco consisting of over 300 parts and 70,000 triangles, a textured lion model consisting of 49 parts and 86,000 triangles, and a textured, wrinkled torus consisting of 79,000 triangles.
Singularities in nonuniform tensor fields
Authors: Yingmei Lavin, Yuval Levy, Lambertus Hesselink
Published at Vis, 1997

Studies the topology of 2nd-order symmetric tensor fields. Degenerate points are basic constituents of tensor fields. From the set of degenerate points, an experienced researcher can reconstruct a whole tensor field. We address the conditions for the existence of degenerate points and, based on these conditions, we predict the distribution of degenerate points inside the field. Every tensor can be decomposed into a deviator and an isotropic tensor. A deviator determines the properties of a tensor field, while the isotropic part provides a uniform bias. Deviators can be 3D or locally 2D. The triple-degenerate points of a tensor field are associated with the singular points of its deviator and the double-degenerate points of a tensor field have singular local 2D deviators. This provides insights into the similarity of topological structure between 1st-order (or vectors) and 2nd-order tensors. Control functions are in charge of the occurrences of a singularity of a deviator. These singularities can further be linked to important physical properties of the underlying physical phenomena. For a deformation tensor in a stationary flow, the singularities of its deviator actually represent the area of the vortex core in the field; for a stress tensor, the singularities represent the area with no stress; for a Newtonian flow, compressible flow and incompressible flow as well as stress and deformation tensors share similar topological features due to the similarity of their deviators; for a viscous flow, removing the large, isotropic pressure contribution dramatically enhances the anisotropy due to viscosity.
Smooth hierarchical surface triangulations
Authors: Tran S. Gieng, Bernd Hamann, Kenneth I. Joy, Gregory L. Schussman, Issac J. Trotts
Published at Vis, 1997

Presents a new method to produce a hierarchical set of triangle meshes that can be used to blend different levels of detail in a smooth fashion. The algorithm produces a sequence of meshes /spl Mscr//sub 0/, /spl Mscr//sub 1/, /spl Mscr//sub 2/..., /spl Mscr//sub n/, where each mesh /spl Mscr//sub i/ can be transformed to mesh /spl Mscr//sub i+1/ through a set of triangle-collapse operations. For each triangle, a function is generated that approximates the underlying surface in the area of the triangle, and this function serves as a basis for assigning a weight to the triangle in the ordering operation, and for supplying the point to which the triangles are collapsed. This technique allows us to view a triangulated surface model at varying levels of detail while insuring that the simplified mesh approximates the original surface well.
Strategies for effectively visualizing 3D flow with volume LIC
Authors: Victoria Interrante, Chester Grosch
Published at Vis, 1997

This paper discusses strategies for effectively portraying 3D flow using volume line integral convolution. Issues include defining an appropriate input texture, clarifying the distinct identities and relative depths of the advected texture elements, and selectively highlighting regions of interest in both the input and output volumes. Apart from offering insights into the greater potential of 3D LIC as a method for effectively representing flow in a volume, a principal contribution of this work is the suggestion of a technique for generating and rendering 3D visibility-impeding "halos" that can help to intuitively indicate the presence of depth discontinuities between contiguous elements in a projection and thereby clarify the 3D spatial organization of elements in the flow. The proposed techniques are applied to the visualization of a hot, supersonic, laminar jet exiting into a colder, subsonic coflow.
Terascale Visualization: Approaches, Pitfalls And Issues
Authors: Carol L. Hunter, Roger Crawfis, Michael Cox, Bernd Hamann, Charles D. Hansen, Mark C. Miller
Published at Vis, 1997

Author(s): Cox, M. B.; Crawfis, Roger; Hamann, Bernd; Hanson, C.; Miller, Mark | Editor(s): Yagel, R.; Hagen, Hans | Abstract: Massively Parallel Supercomputers are once again quickly outpacing our ability to organize, manage and understand the prodigious amounts of data they generate. Graphics technology and algorithms have greatly aided in analyzing the modest datasets of years past, but rarely with enough interactivity to squelch the enduser's exploratory questions. Will computer graphics and scientific visualization or even computional science proceed as status quo or are new paradigm sifts needed? What is the architecture of tomorrow's high-end visualization systems? How much data can we even expect to pull off of these masively parallel machines? What are the new computer graphics technologies that can aid in teracale visulaization? This panel, leverging the panelists past experience and their current knowledge of the field, will provide visions (or dilemma's) for what the next stage or stages of scientific visualization and data management will look like.
The contour spectrum
Authors: Chandrajit L. Bajaj, Valerio Pascucci, Daniel Schikore
Published at Vis, 1997

The authors introduce the contour spectrum, a user interface component that improves qualitative user interaction and provides real-time exact quantification in the visualization of isocontours. The contour spectrum is a signature consisting of a variety of scalar data and contour attributes, computed over the range of scalar values /spl omega//spl isin/R. They explore the use of surface, area, volume, and gradient integral of the contour that are shown to be univariate B-spline functions of the scalar value /spl omega/ for multi-dimensional unstructured triangular grids. These quantitative properties are calculated in real-time and presented to the user as a collection of signature graphs (plots of functions of /spl omega/) to assist in selecting relevant isovalues /spl omega//sub 0/ for informative visualization. For time-varying data, these quantitative properties can also be computed over time, and displayed using a 2D interface, giving the user an overview of the time-varying function, and allowing interaction in both isovalue and time step. The effectiveness of the current system and potential extensions are discussed.
The motion map: efficient computation of steady flow animations
Authors: Bruno Jobard, Wilfrid Lefer
Published at Vis, 1997

The paper presents a new approach for animating 2D steady flow fields. It is based on an original data structure called the motion map. The motion map contains not only a dense representation of the flow field but also all the motion information required to animate the flow. An important feature of this method is that it allows, in a natural way, cyclical variable-speed animations. As far as efficiency is concerned, the advantage of this method is that computing the motion map does not take more time than computing a single still image of the flow and the motion map has to be computed only once. Another advantage is that the memory requirements for a cyclical animation of an arbitrary number of frames amounts to the memory cost of a single still image.