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Item A Parallel Approach to Compression and Decompression of Triangle Meshes using the GPU(The Eurographics Association and John Wiley & Sons Ltd., 2017) Jakob, Johannes; Buchenau, Christoph; Guthe, Michael; Bærentzen, Jakob Andreas and Hildebrandt, KlausMost state-of-the-art compression algorithms use complex connectivity traversal and prediction schemes, which are not efficient enough for online compression of large meshes. In this paper we propose a scalable massively parallel approach for compression and decompression of large triangle meshes using the GPU. Our method traverses the input mesh in a parallel breadth-first manner and encodes the connectivity data similarly to the well known cut-border machine. Geometry data is compressed using a local prediction strategy. In contrast to the original cut-border machine, we can additionally handle triangle meshes with inconsistently oriented faces. Our approach is more than one order of magnitude faster than currently used methods and achieves competitive compression rates.Item 3-D Digital Preservation of At-Risk Global Cultural Heritage(The Eurographics Association, 2016) Lercari, Nicola; Shulze, Jurgen; Wendrich, Willeke; Porter, Benjamin; Burton, Margie; Levy, Thomas E.; Chiara Eva Catalano and Livio De LucaRecent current events have dramatically highlighted the vulnerability of the world's material cultural heritage. The 3-D Digital Preservation of At-Risk Global Cultural Heritage project, led by Thomas Levy at UC San Diego, catalyzes a collaborative research effort by four University of California campuses (San Diego, Berkeley, Los Angeles and Merced) to use cyberarchaeology and computer graphics for cultural heritage to document and safeguard virtually some of the most at-risk heritage objects and places. Faculty and students involved in this project are conducting path-breaking archaeological research - covering more than 10,000 years of culture and architecture - in Cyprus, Greece, Egypt, Ethiopia, Israel, Jordan, Morocco, Turkey, and the United States. This project uses the 3-D archaeological data collected in numerous at-risk heritage places to study, forecast, and model the effects of human conflict, climate change, natural disasters and technological and cultural changes on these sites and landscapes. The greater challenge undertaken by this project is to integrate archaeological heritage data and digital heritage data using the recently-announced Pacific Research Platform (PRP) and its 10-100Gb/s network as well as virtual reality kiosks installed in each participating UC campus. Our aim is to link UC San Diego and the San Diego Supercomputer Center to other labs, libraries and museums at the other UC campuses to form a highly-networked collaborative platform for curation, analysis, and visualization of 3D archaeological heritage data.Item Understanding the Efficiency of GPU Algorithms for Matrix-Matrix Multiplication(The Eurographics Association, 2004) Fatahalian, K.; Sugerman, J.; Hanrahan, P.; Tomas Akenine-Moeller and Michael McCoolUtilizing graphics hardware for general purpose numerical computations has become a topic of considerable interest. The implementation of streaming algorithms, typified by highly parallel computations with little reuse of input data, has been widely explored on GPUs. We relax the streaming model's constraint on input reuse and perform an in-depth analysis of dense matrix-matrix multiplication, which reuses each element of input matrices O(n) times. Its regular data access pattern and highly parallel computational requirements suggest matrix-matrix multiplication as an obvious candidate for efficient evaluation on GPUs but, surprisingly we find even nearoptimal GPU implementations are pronouncedly less efficient than current cache-aware CPU approaches. We find the key cause of this inefficiency is that the GPU can fetch less data and yet execute more arithmetic operations per clock than the CPU when both are operating out of their closest caches. The lack of high bandwidth access to cached data will impair the performance of GPU implementations of any computation featuring significant input reuse.Item Iso Photographic Rendering(The Eurographics Association, 2018) Porral, Philippe; Lucas, Laurent; Muller, Thomas; Randrianandrasana, Joël; Reinhard Klein and Holly RushmeierIn the field of computer graphics, the simulation of the visual appearance of materials requires an accurate computation of the light transport equation. Consequently, material models need to take into account various factors which may influence the spectral radiance perceived by the human eye. Though numerous relevant studies on the reflectance properties of materials have been conducted to date, environment maps used to simulate visual behaviors remain chiefly trichromatic. Whereas questions regarding the accurate characterization of natural lighting have been raised for some time, there are still no real sky environment maps that include both spectral radiance and polarization data. Under these conditions the simulations carried out are approximate and therefore insufficient for the industrial world where investment-sensitive decisions are often made based on these very calculations.Item Real-Time Bump Map Synthesis(The Eurographics Association, 2001) Kautz, Jan; Heidrich, Wolfgang; Seidel, Hans-Peter; Kurt Akeley and Ulrich NeumannIn this paper we present a method that automatically synthesizes bump maps at arbitrary levels of detail in real-time. The only input data we require is a normal density function; the bump map is generated according to that function. It is also used to shade the generated bump map. The technique allows to infinitely zoom into the surface, because more (consistent) detail can be created on the fly. The shading of such a surface is consistent when displayed at different distances to the viewer (assuming that the surface structure is self-similar). The bump map generation and the shading algorithm can also be used separately.Item Polygon Rendering on a Stream Architecture(The Eurographics Association, 2000) Owens, John D.; Dally, William J.; Kapasi, Ujval J.; Rixner, Scott; Mattson, Peter; Mowery, Ben; I. Buck and G. Humphreys and P. HanrahanThe use of a programmable stream architecture in polygon rendering provides a powerful mechanism to address the high performance needs of today s complex scenes as well as the need for flexibility and programmability in the polygon rendering pipeline. We describe how a polygon rendering pipeline maps into data streams and kernels that operate on streams, and how this mapping is used to implement the polygon rendering pipeline on Imagine, a programmable stream processor. We compare our results on a cycleaccurate simulation of Imagine to representative hardware and software renderers.Item Contact-Invariant Optimization for Hand Manipulation(The Eurographics Association, 2012) Mordatch, Igor; Popovic, Zoran; Todorov, Emanuel; Jehee Lee and Paul KryWe present a method for automatic synthesis of dexterous hand movements, given only high-level goals specifying what should happen to the object being manipulated. Results are presented on a wide range of tasks including grasping and picking up objects, twirling them between the fingers, tossing and catching, drawing. This work is an extension of the recent contact-invariant optimization (CIO) method, which introduced auxiliary decision variables directly specifying when and where contacts should occur, and optimized these variables together with the movement trajectory. Our contribution here is extending the unique contact model used in CIO which was specific to locomotion tasks, as well as applying the extended method systematically to hand manipulation.Item Variable Length Coding for GPU-Based Direct Volume Rendering(The Eurographics Association, 2016) Guthe, Stefan; Goesele, Michael; Matthias Hullin and Marc Stamminger and Tino WeinkaufThe sheer size of volume data sampled in a regular grid requires efficient lossless and lossy compression algorithms that allow for on-the-fly decompression during rendering. While all hardware assisted approaches are based on fixed bit rate block truncation coding, they suffer from degradation in regions of high variation while wasting space in homogeneous areas. On the other hand, vector quantization approaches using texture hardware achieve an even distribution of error in the entire volume at the cost of storing overlapping blocks or bricks. However, these approaches suffer from severe blocking artifacts that need to be smoothed over during rendering. In contrast to existing approaches, we propose to build a lossy compression scheme on top of a state-of-the-art lossless compression approach built on non-overlapping bricks by combining it with straight forward vector quantization. Due to efficient caching and load balancing, the rendering performance of our approach improves with the compression rate and can achieve interactive to real-time frame rates even at full HD resolution.Item Parallel Collision Detection Oriented to Distributed Memory Architectures for High-Resolution Meshes(The Eurographics Association, 2021) Novalbos, Marcos; Sánchez, Alberto; Silva, F. and Gutierrez, D. and Rodríguez, J. and Figueiredo, M.Higher resolution meshes should be used in graphics applications to make them as realistic as they can. However, they imply a high computational. Several approaches have been built to solve collision detection, although most of them do not take into account this feature. This paper presents a scalable parallel algorithm for collision detection designed for working with high resolution meshes. The algorithm is based on distributed memory architectures taking advantage of their benefits and overcoming their drawbacks.Item Ray-Traced Collision Detection: Interpenetration Control and Multi-GPU Performance(The Eurographics Association, 2013) Lehericey, Francois; Gouranton, Valérie; Arnaldi, Bruno; Betty Mohler and Bruno Raffin and Hideo Saito and Oliver StaadtWe proposed in [LGA13] an iterative ray-traced collision detection algorithm (IRTCD) that exploits spatial and temporal coherency and proved to be computationally efficient but at the price of some geometrical approximations that allow more interpenetration than needed. In this paper, we present two methods to efficiently control and reduce the interpenetration without noticeable computation overhead. The first method predicts the next potentially colliding vertices. These predictions are used to make our IRTCD algorithm more robust to the above-mentioned approximations, therefore reducing the errors up to 91%. We also present a ray re-projection algorithm that improves the physical response of ray-traced collision detection algorithm. This algorithm also reduces, up to 52%, the interpenetration between objects in a virtual environment. Our last contribution shows that our algorithm, when implemented on multi-GPUs architectures, is far faster.