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Scalable rendering of massive triangle meshes on light field displays

COMPUTERS & GRAPHICS-UK 2008年第1期32卷 55-64页

作者： Bettio, Fabio Gobbetti, Enrico Marton, Fabio Pintore, Giovanni POLARIS CRS4 I-09010 Pula CA Italy

We report on a multiresolution rendering system driving light field displays based on a specially arranged array of projectors and a holographic screen. The system gives multiple freely moving naked-eye viewers the illusion of seeing and manipulating 3D objects with continuous viewer-independent parallax. Multiresolution techniques which take into account the displayed light field geometry are employed to dynamically adapt model resolution to display capabilities and timing constraints. The approach is demonstrated on two different scales: a desktop PC driving a 7.4 Mbeams TV-size display, and a cluster-parallel solution driving a large (1.6 x 0.9 m) 35Mbeams display which supports a room-size working space. In both cases, massive meshes of tens of millions of triangles are manipulated at interactive rates. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： 3D displays massive datasets out-of-core algorithms parallel graphics level of detail

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Automatic partitioning of parallel loops with parallelepiped-shaped tiles

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2002年第5期13卷 460-470页

作者： Rastello, F Robert, Y ST Microelect Grenoble France ENS Lyon UMR CNRS INRIA 5668 LIPComp Sci Lab F-69364 Lyon 07 France

In this paper, an efficient algorithm to implement loop partitioning is introduced and evaluated. We start from results of Agarwal et al. [1] whose aim is to minimize the number of accessed data throughout the computation of a tile: this number is called the cumulative footprint of the tile. We improve these results along several directions. First, we derive a new formulation of the cumulative footprint, allowing for an analytical solution of the optimization problem stated in [1]. Second, we deal with arbitrary parallelepiped-shaped tiles, as opposed to rectangular tiles in [1]. We design an efficient heuristic to determine the optimal tile shape in this general setting and we show its usefulness using both examples from [1] and a large collection of randomly generated data.

关键词： compilation technique hierarchical memory systems loop partitioning tiling cache data locality footprint out-of-core algorithms

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A Local Graph-Based Structure for Processing Gigantic Aggregated 3D Point Clouds

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IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2022年第8期28卷 2822-2833页

作者： Bletterer, Arnaud Payan, Frederic Antonini, Marc Univ Cote dAzur I3S CNRS Nice France

We present an original workflow for structuring a point cloud generated from several scans. Our representation is based on a set of local graphs. Each graph is constructed from the depth map provided by each scan. The graphs are then connected together via the overlapping areas, and careful consideration of the redundant points in these regions leads to a piecewise and globally consistent structure for the underlying surface sampled by the point cloud. The proposed workflow allows structuring aggregated point clouds, scan after scan, whatever the number of acquisitions and the number of points per acquisition, even on computers with very limited memory capacities. To show that our structure can be highly relevant for the community, where the gigantic amount of data represents a real scientific challenge per se, we present an algorithm based on this structure capable of resampling billions of points on standard computers. This application is particularly attractive for simplifying and visualizing gigantic point clouds representing very large-scale scenes (buildings, urban scenes, historical sites...), which often require a prohibitive number of points to describe them accurately.

关键词： Three-dimensional displays Surface morphology Random access memory Surface treatment Solid modeling Sensors Two dimensional displays Computational geometry and object modeling three-dimensional graphics and realism 3D point clouds data structure graphs out-of-core algorithms poisson-disk sampling

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Streaming simplification of tetrahedral meshes

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IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2007年第1期13卷 145-155页

作者： Vo, Huy T. Callahan, Steven P. Lindstrom, Peter Pascucci, Valerio Silva, Claudio T. Sci Comp & Imaging Inst Salt Lake City UT 84112 USA Lawrence Livermore Natl Lab Ctr Appl Sci Comp Livermore CA 94551 USA Univ Utah Sch Comp Salt Lake City UT 84112 USA

Unstructured tetrahedral meshes are commonly used in scientific computing to represent scalar, vector, and tensor fields in three dimensions. Visualization of these meshes can be difficult to perform interactively due to their size and complexity. By reducing the size of the data, we can accomplish real-time visualization necessary for scientific analysis. We propose a two-step approach for streaming simplification of large tetrahedral meshes. Our algorithm arranges the data on disk in a streaming, I/O-efficient format that allows coherent access to the tetrahedral cells. A quadric-based simplification is sequentially performed on small portions of the mesh in-core. Our output is a coherent streaming mesh which facilitates future processing. Our technique is fast, produces high quality approximations, and operates out-of-core to process meshes too large for main memory.

关键词： computational geometry and object modeling out-of-core algorithms streaming algorithms mesh simplification large meshes tetrahedral meshes

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An Input/output Efficient Algorithm for Hessenberg Reduction

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INTERNATIONAL JOURNAL OF FOUNDATIONS OF COMPUTER SCIENCE 2019年第8期30卷 1279-1300页

作者： Mohanty, Sraban Kumar Sajith, G. PDPM Indian Inst Informat Technol Design & Mfg Comp Sci & Engn Jabalpur MP India Indian Inst Technol Guwahati Comp Sci & Engn Gauhati Assam India

Reduction of an N x N nonsymmetric matrix to Hessenberg form which takes O(N-3) flops and O(N-3/B) I/Os is a major performance bottleneck in the computing of its eigenvalues. Usually to improve the performance, this Hessenberg reduction is computed in two steps: the first one reduces the matrix to a banded Hessenberg form, and the second one further reduces it to Hessenberg form by incorporating more matrix-matrix operations in the computation. We analyse the two steps of the Hessenberg reduction problem on the external memory model (of Aggarwal and Vitter) for their I/O complexities. We propose and analyse a tile based algorithm for the first step of the reduction and show that it takes O(N-3/B min{t, root M}) I/Os. For the reduction of a banded Hessenberg matrix of bandwidth t to Hessenberg form, we propose an algorithm, which uses tight packing of bulges, and requires only O(t(2)N(2)/B + N-3/tB) I/Os. Combining the results of the two steps of the reduction, we show that the Hessenberg reduction can be performed in O(N-3/root MB) I/Os, when N is sufficiently large. To the best of our knowledge, the proposed algorithm is the first I/O optimal algorithm for Hessenberg reduction;the worst case I/O complexity matches the known lower bound of the problem.

关键词： External memory algorithms out-of-core algorithms matrix computations Hessenberg reduction I/O efficient matrix computation

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Real-time optimal adaptation for planetary geometry and texture: 4-8 tile hierarchies

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IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2005年第4期11卷 355-368页

作者： Hwa, LM Duchaineau, MA Joy, KI Lawrence Livermore Natl Lab Livermore CA 94551 USA Univ Calif Davis Inst Data Anal & Visualizat Davis CA 95616 USA Univ Calif Davis Dept Comp Sci Davis CA 95616 USA

The real-time display of huge geometry and imagery databases involves view-dependent approximations, typically through the use of precomputed hierarchies that are selectively refined at runtime. A classic motivating problem is terrain visualization in which planetary databases involving billions of elevation and color values are displayed on PC graphics hardware at high frame rates. This paper introduces a new diamond data structure for the basic selective-refinement processing, which is a streamlined method of representing the well-known hierarchies of right triangles that have enjoyed much success in real-time, view-dependent terrain display. Regular-grid tiles are proposed as the payload data per diamond for both geometry and texture. The use of 4-8 grid refinement and coarsening schemes allows level-of-detail transitions that are twice as gradual as traditional quadtree-based hierarchies, as well as very high-quality low-pass filtering compared to subsampling-based hierarchies. An out-of-core storage organization is introduced based on Sierpinski indices per diamond, along with a tile preprocessing framework based on fine-to-coarse, same-level, and coarse-to-fine gathering operations. To attain optimal frame-to-frame coherence and processing-order priorities, dual split and merge queues are developed similar to the Realtime Optimally Adapting Meshes ( ROAM) Algorithm, as well as an adaptation of the ROAM frustum culling technique. Example applications of lake-detection and procedural terrain generation demonstrate the flexibility of the tile processing framework.

关键词： large data set visualization level-of-detail techniques view dependent visualization adaptive textures out-of-core algorithms procedural terrain generation

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Large mesh simplification using processing sequences 03

Large mesh simplification using processing sequences

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IEEE Visualization 2003 Conference

作者： Isenburg, M Lindstrom, P Gumhold, S Snoeyink, J Univ N Carolina Chapel Hill NC 27514 USA

ISBN: (纸本)0780381203

In this paper we show how out-of-core mesh processing techniques can be adapted to pet-form their computations based on the new processing sequence paradigm [Isenburg and Gumhold 2003;Isenburg et al. 2003], using mesh simplification as an example. We believe that this processing concept will also prove useful for other tasks, such as parameterization, remeshing, or smoothing, for which currently only in-core solutions exist. A processing sequence represents a mesh as a particular interleaved ordering of indexed triangles and vertices. This representation allows streaming very large meshes through main memory while maintaining information about the visitation status of edges and vertices. At any time, only a small portion of the mesh is kept in-core, with the bulk of the mesh data residing on disk. Mesh access is restricted to a fixed traversal order, but full connectivity and geometry information is available for the active elements of the traversal. This provides seamless and highly efficient out-of-core access to very large meshes for algorithms that can adapt their computations to this fixed ordering. The two abstractions that are naturally supported by this representation are boundary-based and buffer-based processing. We illustrate both abstractions by adapting two different simplification methods to perform their computation using a prototype of our mesh processing sequence API. Both algorithms benefit from using processing sequences in terms of improved quality, more efficient execution, and smaller memory footprints.

关键词： out-of-core algorithms processing sequences mesh simplification large meshes

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High-quality networked terrain rendering from compressed bitstreams 07

High-quality networked terrain rendering from compressed bit...

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12th International Conference on 3D Web Technology

作者： Bettio, Fabio Gobbetti, Enrico Marton, Fabio Pintore, Giovanni CRS4 Visual Comp Grp I-09010 Pula Italy

ISBN: (纸本)9781595936523

We describe a compressed multiresolution representation and a client-server architecture for supporting interactive high quality remote visualization of very large textured planar and spherical terrains. Our approach incrementally updates a chunked level-of-detail BDAM hierarchy by using precomputed wavelet coefficient matrices decoded from a compressed bitstream originating from a thin server. The structure combines the aggressive compression rates of wavelet-based image representations with the ability to ensure over-all geometric continuity for variable resolution views of planar and spherical terrains with no need for run-time stitching. The efficiency of the approach is demonstrated on a large scale interactive remote visualization of global and local terrains on ADSL networks. A library implementing an early version of this work has been incorporated into a widely distributed geo-viewing system with tens of thousands of clients.

关键词： out-of-core algorithms Network Streaming Data Compression Level of Detail

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Far voxels: A multiresolution framework for interactive rendering of huge complex 3D models on commodity graphics platforms

Far voxels: A multiresolution framework for interactive rend...

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ACM SIGGRAPH 2005 Conference

作者： Gobbetti, E Marton, F CRS4 Visual Comp Grp POLARIS Edificio 1 I-09010 Pula Italy

We present an efficient approach for end-to-end out-of-core construction and interactive inspection of very large arbitrary surface models. The method tightly integrates visibility culling and out-of-core data management with a level-of-detail framework. At preprocessing time, we generate a coarse volume hierarchy by binary space partitioning the input triangle soup. Leaf nodes partition the original data into chunks of a fixed maximum number of triangles, while inner nodes are discretized into a fixed number of cubical voxels. Each voxel contains a compact direction dependent approximation of the appearance of the associated volumetric sub-part of the model when viewed from a distance. The approximation is constructed by a visibility aware algorithm that fits parametric shaders to samples obtained by casting rays against the full resolution dataset. At rendering time, the volumetric structure, maintained off-core, is refined and rendered in front-to-back order, exploiting vertex programs for GPU evaluation of view-dependent voxel representations, hardware occlusion queries for culling occluded subtrees, and asynchronous I/O for detecting and avoiding data access latencies. Since the granularity of the multiresolution structure is coarse, data management, traversal and occlusion culling cost is amortized over many graphics primitives. The efficiency and generality of the approach is demonstrated with the interactive rendering of extremely complex heterogeneous surface models on current commodity graphics platforms.

关键词： out-of-core algorithms level of detail

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A memory insensitive technique for large model simplification

A memory insensitive technique for large model simplificatio...

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IEEE Visualization Conference

作者： Lindstrom, P Silva, CT Lawrence Livermore Natl Lab Ctr Appl Sci Comp Livermore CA 94551 USA

ISBN: (纸本)078037200X

In this paper we propose three simple, but significant improvements to the OoCS (out-of-core Simplification) algorithm of Lindstrom [20] which increase the quality of approximations and extend the applicability of the algorithm to an even larger class of compute systems. The original OoCS algorithm has memory complexity that depends on the size of the output mesh. but no dependency on the size of the input mesh, That is, it can be used to simplify meshes of arbitrarily large size, but the complexity of the output mesh is limited by the amount of memory available. Our first contribution is a version of OoCS that removes the dependency of having enough memory to hold (even) the simplified mesh. With our new algorithm. the whole process is made essentially independent of the available memory on the host computer. Our new technique uses disk instead of main memory, but it is carefully designed to avoid costly random accesses. Our two other contributions improve the quality of the approximations generated by OoCS. We propose a scheme for preserving surface boundaries which does not use connectivity information, and a scheme for constraining the position of the "representative vertex" of a grid cell to an optimal position inside the cell.

关键词： polygonal surface simplification large data out-of-core algorithms external sorting quadric error metrics

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