Advances in 3D scanning technologies have enabled the practical creation of meshes with hundreds of millions of polygons. Traditional algorithms for display, simplification, and progressive transmission of meshes are impractical for data sets of this size. We describe a system for representing and progressively displaying these meshes that combines a multiresolution hierarchy based on bounding spheres with a rendering system based on points. A single data structure is used for view frustum culling, backface culling, level-of-detail selection, and rendering. The representation is compact and can be computed quickly, making it suitable for large data sets. Our implementation, written for use in a large-scale 3D digitization project, launches quickly, maintains a user-settable interactive frame rate regardless of object complexity or camera position, yields reasonable image quality during motion, and refines progressively when idle to a high final image quality. We have demonstrated the system on scanned models containing hundreds of millions of samples.

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QSplat: a multiresolution point rendering system for large meshes

Level-of-detail (LOD) representations are an important tool for realtime rendering of complex geometric environments. The previously introduced progressive mesh representation defines for an arbitrary triangle mesh a sequence of approximating meshes optimized for view-independent LOD. In this paper, we introduce a framework for selectively refining an arbitrary progressive mesh according to changing view parameters. We define efficient refinement criteria based on the view frustum, surface orientation, and screen-space geometric error, and develop a real-time algorithm for incrementally refining and coarsening the mesh according to these criteria. The algorithm exploits view coherence, supports frame rate regulation, and is found to require less than 15% of total frame time on a graphics workstation. Moreover, for continuous motions this work can be amortized over consecutive frames. In addition, smooth visual transitions (geomorphs) can be constructed between any two selectively refined meshes. A number of previous schemes create view-dependent LOD meshes for height fields (e.g. terrains) and parametric surfaces (e.g. NURBS). Our framework also performs well for these special cases. Notably, the absence of a rigid subdivision structure allows more accurate approximations than with existing schemes. We include results for these cases as well as for general meshes. CR Categories: I.3.3 [Computer Graphics]: Picture/Image Generation Display algorithms; I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling surfaces and object representations. Additional

https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/vdrpm.pdf

View-dependent refinement of progressive meshes

From the Publisher:
Level of detail (LOD) techniques are increasingly used by professional real-time developers to strike the balance between breathtaking virtual worlds and smooth, flowing animation. Level of Detail for 3D Graphics brings together, for the first time, the mechanisms, principles, practices, and theory needed by every graphics developer seeking to apply LOD methods.
Continuing advances in level of detail management have brought this powerful technology to the forefront of 3D graphics optimization research. This book, written by the very researchers and developers who have built LOD technology, is both a state-of-the-art chronicle of LOD advances and a practical sourcebook, which will enable graphics developers from all disciplines to apply these formidable techniques to their own work. 
Features
Is a complete, practical resource for programmers wishing to incorporate LOD technology into their own systems. Is an important reference for professionals in game development, computer animation, information visualization, real-time graphics and simulation, data capture and preview, CAD display, and virtual worlds. Is accessible to anyone familiar with the essentials of computer science and interactive computer graphics. Covers the full range of LOD methods from mesh simplification to error metrics, as well as advanced issues of human perception, temporal detail, and visual fidelity measurement. Includes an accompanying Web site rich in supplementary material including source code, tools, 3D models, public domain software, documentation, LOD updates, and more. 

Author Biography:David Luebke
David is an Assistant Professor in the Department of Computer Science at the University of Virginia. His principal research interest is the problem of rendering very complex scenes at interactive rates. His research focuses on software techniques such as polygonal simplification and occlusion culling to reduce the complexity of such scenes to manageable levels. Luebke's dissertation research, summarized in a SIGGRAPH '97 paper, introduced a dynamic, view-dependent approach to polygonal simplification for interactive rendering of extremely complex CAD models. He earned his Ph.D. at the University of North Carolina, and his Bachelors degree at the Colorado College. 
Martin Reddy
Martin is a Senior Computer Scientist at SRI International where he works in the area of terrain visualization. This work involves the real-time display of massive terrain databases that are distributed over wide-area networks. His research interests include level of detail, visual perception, and computer graphics. His doctoral research involved the application of models of visual perception to real-time computer graphics systems, enabling the selection of level of detail based upon measures of human perception. He received his B.Sc. from the University of Strathclyde and his Ph.D. from the University of Edinburgh, UK. He is on the Board of Directors of the Web3D Consortium and chair of the GeoVRML Working Group. 
Jonathan D. Cohen
Jon is an Assistant Professor in the Department of Computer Science at The Johns Hopkins University. He earned his Doctoral and Masters degrees from The University of North Carolina at Chapel Hill and earned his Bachelors degree from Duke University. His interests include polygonal simplification and other software acceleration techniques, parallel rendering architectures, collision detection, and high-quality interactive computer graphics. 
Amitabh Varshney
Amitabh is an Associate Professor in the Department of Computer Science at the University of Maryland. His research interests lie in interactive computer graphics, scientific visualization, molecular graphics, and CAD. Varshney has worked on several aspects of level-of-detail simplifications including topology-preserving and topology-reducing simplifications, view-dependent simplifications, parallelization of simplification computation, as well as using triangle strips in multiresolution rendering. Varshney received his PhD and MS from the University of North Carolina at Chapel Hill in 1994 and 1991 respectively. He received his B. Tech. in Computer Science from the Indian Institute of Technology at Delhi in 1989. 
Benjamin Watson
Ben is an Assistant Professor in Computer Science at Northwestern University. He earned his doctoral and Masters degrees at Georgia Tech's GVU Center, and his Bachelors degree at the University of California, Irvine. His dissertation focused on user performance effects of dynamic level of detail management. His other research interests include object simplification, medical applications of virtual reality, and 3D user interfaces. 
Robert Huebner
Robert is the Director of Technology at Nihilistic Software, an independent development studio located in Marin County, California. Prior to co-founding Nihilistic, Robert has worked on a number of successful game titles including "Jedi Knight: Dark Forces 2" for LucasArts Entertainment, "Descent" for Parallax Software, and "Starcraft" for Blizzard Entertainment. Nihilistic's first title, "Vampire The Masquerade: Redemption" was released for the PC in 2000 and sold over 500,000 copies worldwide. Nihilistic's second project will be released in the Winter of 2002 on next-generation game consoles. Robert has spoken on game technology topics at SIGGRAPH, the Game Developer's Conference (GDC), and Electronic Entertainment Expo (E3). He also serves on the advisory board for the Game Developer's Conference and the International Game Developer's Association (IGDA). Robert's e-mail address is .

Level of Detail for 3D Graphics

This dissertation describes hierarchical dynamic simplification (HDS), a new approach to the problem of simplifying arbitrary polygonal environments. HDS is dynamic, retessellating the scene continually as the user's viewing position shifts, and global, processing the entire database without first decomposing the environment into individual objects. The resulting system enables real-time display of very complex polygonal CAD models consisting of thousands of parts and millions of polygons. HDS supports various preprocessing algorithms and various run-time criteria, providing a general framework for dynamic view-dependent simplification. 
Briefly, HDS works by clustering vertices together in a hierarchical fashion. The simplification process continually queries this hierarchy to generate a scene containing only those polygons that are important from the current viewpoint. When the volume of space associated with a vertex cluster occupies less than a user-specified amount of the screen, all vertices within that cluster are collapsed together and degenerate polygons filtered out. HDS maintains an active list of visible polygons for rendering. Since frame-to-frame movements typically involve small changes in viewpoint, and therefore modify this list by only a few polygons, the method takes advantage of temporal coherence for greater speed.

/pdf/view-dependent-simplification-of-arbitrary-polygonal-54r55u3e2x.pdf

View-dependent simplification of arbitrary polygonal environments

A virtual surgery system or virtual testing system provides a simulation or test based on image data. A simulator combined with a real exam requires simulation tasks by a test taker. Additionally, a surgical procedure may be simulated using image data of a patient in devices simulating the physical instruments a surgeon uses in performing the actual procedure, for example. The user input device, such as a mouse, three dimensional mouse, joystick, seven dimensional joystick, full size simulator, etc., can be used in a virtual simulation to move through the image data while the user looks at the data and interaction of the input device with the image data on a display screen. Force feedback can be provided based on physical constraint models (of the anatomy, for example), or based on edge and collision detection between the virtual scope or virtual tool used by the operator and walls or edges of the image data in the image space. The virtual simulator may be used as a teaching, training, testing, demonstration, or remote telesurgery device, for example.

Virtual surgery system

The cone of normals technique for curved surface patches allows to perform various quick tests at the patch level such as front- or backfacing test, light influence test, and existence of silhouette edges test. For a given patch, a truncated cone of normals is constructed at creation time, which contains all points and all normal directions of the patch. At traversal time, a simple scalar product test determines whether the whole patch is backfacing or frontfacing, so that the costly step of tessellating the patch is avoided in case of patch level face culling. In addition, the technique quickly determines which light sources have no influence on a patch, and which patches have no silhouette edges. The technique can also be used for other surface primitives, such as triangular strips and quadrilateral meshes,

Salim S. Abi-Ezzi

Papers

The Cone of Normals Technique for Fast Processing of Curved Patches