Results 1  10
of
52
HardwareAccelerated Volume and Isosurface Rendering Based on CellProjection
, 2000
"... We present two beneficial rendering extensions to the Projected Tetrahedra (PT) algorithm by Shirley and Tuchman. These extensions are compatible with any cell sorting technique, for example the BSPXMPVO sorting algorithm for unstructured meshes. ..."
Abstract

Cited by 85 (13 self)
 Add to MetaCart
We present two beneficial rendering extensions to the Projected Tetrahedra (PT) algorithm by Shirley and Tuchman. These extensions are compatible with any cell sorting technique, for example the BSPXMPVO sorting algorithm for unstructured meshes.
The state of the art in flow visualization: Dense and texturebased techniques
 Computer Graphics Forum
, 2004
"... Flow visualization has been a very attractive component of scientific visualization research for a long time. Usually very large multivariate datasets require processing. These datasets often consist of a large number of sample locations and several time steps. The steadily increasing performance of ..."
Abstract

Cited by 65 (16 self)
 Add to MetaCart
Flow visualization has been a very attractive component of scientific visualization research for a long time. Usually very large multivariate datasets require processing. These datasets often consist of a large number of sample locations and several time steps. The steadily increasing performance of computers has recently become a driving factor for a reemergence in flow visualization research, especially in texturebased techniques. In this paper, dense, texturebased flow visualization techniques are discussed. This class of techniques attempts to provide a complete, dense representation of the flow field with high spatiotemporal coherency. An attempt of categorizing closely related solutions is incorporated and presented. Fundamentals are shortly addressed as well as advantages and disadvantages of the methods. Categories and Subject Descriptors (according to ACM CCS): I.3 [Computer Graphics]: visualization, flow visualization, computational flow visualization
A High Accuracy Volume Renderer for Unstructured Data
 IEEE Transactions on Visualization and Computer Graphics
, 1998
"... This paper describes a volume rendering system for unstructured data, especially finite element data, that creates images with very high accuracy. The system will currently handle meshes whose cells are either linear or quadratic tetrahedra. Compromises or approximations are not introduced for the s ..."
Abstract

Cited by 52 (6 self)
 Add to MetaCart
This paper describes a volume rendering system for unstructured data, especially finite element data, that creates images with very high accuracy. The system will currently handle meshes whose cells are either linear or quadratic tetrahedra. Compromises or approximations are not introduced for the sake of efficiency. Whenever possible, exact mathematical solutions for the radiance integrals involved and for interpolation are used. The system will also handle meshes with mixed cell types: tetrahedra, bricks, prisms, wedges, and pyramids, but not with high accuracy. Accurate semitransparent shaded isosurfaces may be embedded in the volume rendering. For very small cells, subpixel accumulation by splatting is used to avoid sampling error. A revision to an existing accurate visibility ordering algorithm is described which includes a correction and a method for dramatically increasing its efficiency. Finally, hardware assisted projection and compositing are extended from tetrahedra to arbit...
ZSWEEP: An Efficient and Exact Projection Algorithm for Unstructured Volume Rendering
, 2000
"... We present a simple new algorithm that performs fast and memoryefficient cell projection for (exact) rendering of unstructured datasets. The main idea of the "ZSweep" algorithm is very simple; it is based on sweeping the data with a plane parallel to the viewing plane, in order of increasing z, pro ..."
Abstract

Cited by 46 (14 self)
 Add to MetaCart
We present a simple new algorithm that performs fast and memoryefficient cell projection for (exact) rendering of unstructured datasets. The main idea of the "ZSweep" algorithm is very simple; it is based on sweeping the data with a plane parallel to the viewing plane, in order of increasing z, projecting the faces of cells that are incident to vertices as they are encountered by the sweep plane. The efficiency arises from the fact that the algorithm exploits the implicit (approximate) global ordering that the zordering of the vertices induces on the cells that are incident on them. The algorithm projects cells by projecting each of their faces, with special care taken to avoid double projection of internal faces and to assure correctness in the projection order. The contribution for each pixel is computed in stages, during the sweep, using a short list of ordered face intersections, which is known to be correct and complete at the instant that each stage of the computation is comple...
Accelerating TimeVarying Hardware Volume Rendering Using TSP Trees and ColorBased Error Metrics
, 2000
"... This paper describes a new hardware volume rendering algorithm for timevarying data. The algorithm uses the TimeSpace Partitioning (TSP) tree data structure to identify regions within the data that have spatial or temporal coherence. By using this coherence, the rendering algorithm can improve per ..."
Abstract

Cited by 45 (9 self)
 Add to MetaCart
This paper describes a new hardware volume rendering algorithm for timevarying data. The algorithm uses the TimeSpace Partitioning (TSP) tree data structure to identify regions within the data that have spatial or temporal coherence. By using this coherence, the rendering algorithm can improve performance when the volume data are larger than the texture memory capacity by decreasing the amount of textures required. This coherence can also allow improved speed by appropriately rendering flatshaded polygons instead of textured polygons, and by not rendering transparent regions. To reduce the polygonization overhead caused by the use of the hierarchical data structure, we use a fast incremental polygon slicing algorithm. The paper also introduces new colorbased error metrics, which more accurately identify coherent regions compared to the earlier scalarbased metrics. By showing experimental results from runs using different data sets and error metrics, we demonstrate that the new met...
Multiresolution Representation and Visualization of Volume Data
, 1997
"... A system to represent and visualize scalar volume data at multiple resolution is presented. The system is built on a multiresolution model based on tetrahedral meshes with scattered vertices that can be obtained from any initial dataset. The model is built offline through data simplification techni ..."
Abstract

Cited by 44 (3 self)
 Add to MetaCart
A system to represent and visualize scalar volume data at multiple resolution is presented. The system is built on a multiresolution model based on tetrahedral meshes with scattered vertices that can be obtained from any initial dataset. The model is built offline through data simplification techniques, and stored in a compact data structure that supports fast online access. The system supports interactive visualization of a representation at an arbitrary level of resolution through isosurface and projective methods. The user can interactively adapt the quality of visualization to requirements of a specific application task, and to the performance of a specific hardware platform. Representations at different resolutions can be used together to enhance further interaction and performance through progressive and multiresolution rendering. Index Terms  Volume data visualization, multiresolution representation, tetrahedral meshes. I. Introduction Volume datasets used in current applic...
Fast Rendering of Irregular Grids
, 2007
"... We propose a fast algorithm for rendering general irregular grids. Our method uses a sweepplane approach to accelerate ray casting, and can handle disconnected and nonconvex (even with holes) unstructured irregular grids with a rendering cost that decreases as the “disconnectedness” decreases. The ..."
Abstract

Cited by 43 (11 self)
 Add to MetaCart
We propose a fast algorithm for rendering general irregular grids. Our method uses a sweepplane approach to accelerate ray casting, and can handle disconnected and nonconvex (even with holes) unstructured irregular grids with a rendering cost that decreases as the “disconnectedness” decreases. The algorithm is carefully tailored to exploit spatial coherence even if the image resolution differs substantially from the object space resolution. In this paper, we establish the practicality of our method through experimental results based on our implementation, and we also provide theoretical results, both lower and upper bounds, on the complexity of ray casting of irregular grids.
An Exact Interactive Time Visibility Ordering Algorithm for Polyhedral Cell Complexes
, 1998
"... A visibility ordering of a set of objects, from a given viewpoint, is a total order on the objects such that if object a obstructs object b,thenb precedes a in the ordering. Such orderings are extremely useful for rendering volumetric data. We present an algorithm that generates a visibility orderin ..."
Abstract

Cited by 39 (13 self)
 Add to MetaCart
A visibility ordering of a set of objects, from a given viewpoint, is a total order on the objects such that if object a obstructs object b,thenb precedes a in the ordering. Such orderings are extremely useful for rendering volumetric data. We present an algorithm that generates a visibility ordering of the cells of an unstructured mesh, provided that the cells are convex polyhedra and nonintersecting, and that the visibility ordering graph does not contain cycles. The overall mesh may be nonconvex and it may have disconnected components. Our technique employs the sweep paradigm to determine an ordering between pairs of exterior (mesh boundary) cells which can obstruct one another. It then builds on Williams' MPVO algorithm [33] which exploits the ordering implied by adjacencies within the mesh. The partial ordering of the exterior cells found by sweeping is used to augment the DAG created in Phase II of the MPVO algorithm. Our method thus removes the assumption of the MPVO algorithm t...
The Lazy Sweep Ray Casting Algorithm for Rendering Irregular Grids
 IEEE Transactions on Visualization and Computer Graphics
, 1997
"... Lazy Sweep Ray Casting is a fast algorithm for rendering general irregular grids. It is based on the sweepplane paradigm, and it is able to accelerate ray casting for rendering irregular grids, including disconnected and nonconvex (even with holes) unstructured irregular grids with a rendering cost ..."
Abstract

Cited by 38 (8 self)
 Add to MetaCart
Lazy Sweep Ray Casting is a fast algorithm for rendering general irregular grids. It is based on the sweepplane paradigm, and it is able to accelerate ray casting for rendering irregular grids, including disconnected and nonconvex (even with holes) unstructured irregular grids with a rendering cost that decreases as the "disconnectedness" decreases. The algorithm is carefully tailored to exploit spatial coherence even if the image resolution differs substantially from the object space resolution. Lazy Sweep Ray Casting has several desirable properties, including its generality, (depthsorting) accuracy, low memory consumption, speed, simplicity of implementation and portability (e.g., no hardware dependencies). We establish the practicality of our method through experimental results based on our implementation, which is shown to be substantially faster (by up to two orders of magnitude) than other algorithms implemented in software. We also provide theoretical results, both lower and ...
T.: A scalable parallel cellprojection volume rendering algorithm for 3d unstructured data
 In Proc. 1997 Symposium on Parallel Rendering
, 1997
"... Visualizing threedimensional unstructured data from aerodynamics calculations is challenging because the associated meshes are typically large in size and irregular in both shape and resolution. The goal of this research is to develop a fast, efficient parallel volume rendering algorithm for massiv ..."
Abstract

Cited by 36 (14 self)
 Add to MetaCart
Visualizing threedimensional unstructured data from aerodynamics calculations is challenging because the associated meshes are typically large in size and irregular in both shape and resolution. The goal of this research is to develop a fast, efficient parallel volume rendering algorithm for massively parallel distributedmemory supercomputers consisting of a large number of very powerful processors. We use cellprojection instead of raycasting to provide maximum flexibility in the data distribution and rendering steps. Effective static load balancing is achieved with a round robin distribution of data cells among the processors. A spatial partitioning tree is used to guide the rendering, optimize the image compositing step, and reduce memory consump tion. Communication cost is reduced by buffering messages and by overlapping communication with rendering calculations as much as possible. Tests on the IBM SP2 demonstrate that these strategies provide high rendering rates and good scalability. For a dataset containing half a million tetrahedral cells, we achieve two frames per second for a 400x400pixel image using 128 processors.