OpenSG'03

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https://diglib.eg.org/handle/10.2312/994

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    API Design for Adaptive Subdivision Surfaces
    (The Eurographics Association, 2003) Sovakar, A.; Studnitz, A. von; Kobbelt, L.; Dirk Reiners
    We present an API for adaptive subdivision schemes which is generic in the sense that it allows to define a composite subdivision operator as a sequence of atomic splitting and averaging rules. The API encapsulates a mesh data structure enhanced by additional temporary information which is necessary to enable the refinement of mesh faces in random order while keeping the mesh structure consistent and avoiding redundant computations.
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    Advanced Environment Mapping in VR Applications
    (The Eurographics Association, 2003) Kautz, Jan; Daubert, Katja; Seidel, Hans-Peter; Dirk Reiners
    In this paper, we propose an approach for rendering diffuse and glossy reflections using environment maps. This approach is geared towards VR applications, where realism and fast rendering is important. We exploit certain mathematical properties of diffuse reflections and certain features of graphics hardware for glossy reflections. This results in a very fast, single-pass rendering algorithm, which even allows to dynamically vary the incident lighting.
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    An Occlusion Culling Toolkit for OpenSG PLUS
    (The Eurographics Association, 2003) Staneker, Dirk; Dirk Reiners
    Image-space occlusion culling is an useful approach to reduce the rendering load of large polygonal models in scienti c computing, mechanical engineering, or virtual medicine. Like most large model techniques, occlusion culling trades overhead costs with the rendering costs of the possibly occluded geometry. In this paper we present an occlusion culling toolkit for OpenSG. The toolkit includes three different image space techniques utilizing graphics hardware. These techniques are supported by other software techniques to optimize the occlusion culling queries. All techniques are conservative and usable with dynamic scenes, because no precomputing is necessary.
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    Preserving Realism in Real-Time Rendering of Bidirectional Texture Functions
    (The Eurographics Association, 2003) Meseth, Jan; Müller, Gero; Klein, Reinhard; Dirk Reiners
    The Bidirectional Texture Function (BTF) is a suitable representation for the appearance of highly detailed surface structures under varying illumination and viewing conditions. Since real-time rendering of the full BTF data is currently not feasible, approximations of the six-dimensional BTF are used such that the amount of data is reduced and current graphics hardware can be exploited. While existing methods work well for materials with low depth variation, realism is lost if the depth variation grows. In this paper we analyze this problem and devise a new real-time rendering method, which provides signi cant improvements with respect to realism for such highly structured materials without sacri cing the general applicability and speed of previous algorithms. We combine our approach with texture synthesis methods to drastically reduce the texture memory requirements and demonstrate the capabilities of our new rendering method with several examples.
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    Parallel Architecture of an Interactive Scientific Visualisation System for Large Datasets
    (The Eurographics Association, 2003) Schneider, Sascha; May, Thorsten; Schmidt, Michael; Dirk Reiners
    In this paper we describe a further development state of our system which is able to compute actual scientific and realistic visualization methods in parallel. This paper is related to the basic work we presented in one of our previous articles 18. Our system is capable to integrate easily in modern VR renderers like for example Open Inventor 19, Coin 4 and OpenSG 5. Our approach is designed for processing large datasets which usually are the result of physically based simulation algorithms and programs. Using our techniques it is even more feasible to manage similar visualization problems for other large amounts of data (e.g. medicinal CT-scans or large geometries) in the context of displaying interactively.
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    The OpenRT Application Programming Interface - Towards A Common API for Interactive Ray Tracing
    (The Eurographics Association, 2003) Dietrich, Andreas; Wald, Ingo; Benthin, Carsten; Slusallek, Philipp; Dirk Reiners
    For more than a decade now, interactive graphics has been shaped by triangle rasterization technology and the corresponding OpenGL graphics API. Since recently, however, interactive ray tracing is becoming a reality, and is slowly becoming available on several different hardware platforms. Due to its superior scalability, usability and efficiency, it is likely to play an increasingly important role in future interactive graphics applications. Though it would be desirable to drive this technology with a well-known API such as todays quasi-standard OpenGL interface, this would be complicated due to OpenGL's tight coupling to rasterization technology, which makes it less suitable for ray tracing. In this paper, we propose a new application programming interface called OpenRT. This new API is designed to be as similar to OpenGL as possible, while emphasizing the strength of interactive ray tracing. While being as simple to learn and use as OpenGL, OpenRT offers all the advantages of ray tracing, like implicit visibility culling, instantiation, the freedom to shoot arbitrary rays, and fully programmable shading.
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    Parallel Stereo Visualization For ClustersWith OpenInventor: A Case Study For The Automotive Industry
    (The Eurographics Association, 2003) Vega, Fernando; Suÿner, Gerd; Reuding, Thomas; Greiner, Günther; Dirk Reiners
    Stereo visualization is an area which can greatly benefit from cluster computing due to the parallelizable nature of the rendering task. In order to implement this idea, we have developed a novel software architecture which allows the construction of parallel OpenInventor-based stereo applications. As a result of this work, we present the Open- Inventor Stereo Library for Clusters. The library provides tools to port transparently OpenInventor applications to stereo cluster-based OpenInventor applications. The distribution of the rendering tasks is encapsulated, and the developer does not have to take care of non-graphics-related tasks. Evaluation was carried out on a prototype cluster consisting of a master and two slave rendering Linux PCs. The resulting pair of stereo images was visualized with polarization-filter projector and glasses. A standard X desktop is available and multiple OpenInventor based windowed applications can be used simultaneously. The value of the present work was demonstrated with an example 3D-visualization application for the automotive industry.
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    Frontmatter OpenSG 2013
    (The Eurographics Association, 2003) Dirk Reiners
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    Adaptive Tessellation of Subdivision Surfaces in OpenSG
    (The Eurographics Association, 2003) Settgast, Volker; Müller, Kerstin; Fünfzig, Christoph; Fellner, Dieter W.; Dirk Reiners
    The need for realistic models especially in virtual reality environments leads us to freeform shapes like subdivision surfaces. Based on a standard polygonal mesh, the modeller can build various kinds of shapes using an arbitrary topology and special geometrical features like creases. Nowadays, it also is a part of most standard modelling packages like Maya and 3DStudio Max. However, the interactive display of subdivision surfaces in current scenegraph systems as static level-of-details is unpractical, because of the exponentially increasing number of polygons during the subdivision steps. Therefore an adaptive algorithm, choosing only the necessary quads and triangles, is required to obtain good looking images at high framerates. In this paper we present a rendering algorithm considering the static surface properties like curvature as well as viewdependent properties like silhouette location and projection size. Without modifying the basis mesh, the method works patchwise and tesselates each patch recursively using a new datastructure, called Slate. We show that the algorithm can be implemented efficiently using direct OpenGL. In comparison we consider the algorithm’'s integration into the scenegraph system OpenSG, where the scenegraph node feeds into an indexed-face-set node.
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    A Framework for Dynamic Connectivity Meshes
    (The Eurographics Association, 2003) J.Vorsatz,; Seidel, Hans-Peter; Dirk Reiners
    Implementing algorithms that are based on dynamic triangle meshes often requires updating internal datastructures as soon as the connectivity of the mesh changes. The design of a class hierarchy that is able to deal with such changes is particularly challenging if the system reaches a certain complexity. The paper proposes a software design that enables the users to efficiently implement algorithms that can handle these dynamic changes while still maintaining a certain encapsulation of the single components. Our design is based on a callback mechanism. A client can register at some Info-object and gets informed whenever a change of the connectivity occurs. This way the client is able to keep internal data up-to-date. Our framework enables us to write small client classes that cover just a small dedicated aspect of necessary updates related to the changing connectivity. These small components can be combined to more complex modules and can often easily be reused. Moreover, we do not have to store related 'dynamic data' in one central place, e.g. the mesh, which could lead to a significant memory overhead if an application uses some modules just for a short time. We have used and tested this class design extensively for implementing 'Dynamic Connectivity Meshes and Applications 9'. Additionally, as a feasibility study, we have implemented and integrated our concept in the OpenMesh2- framework.
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    OpenManip: An Extensible Cross-Scene-Graph Framework for Direct Object Manipulation
    (The Eurographics Association, 2003) Braitmaier, Michael; Weiler, Manfred; Ertl, Thomas; Dirk Reiners
    In this paper we describe a framework that exploits 3D widgets in order to allow for the direct manipulation of scene graph objects. The design of the frameworks is inspired by the OpenInventor manipulator functionality, but additionally emphasizes transparency from the underlying scene graph system, by separating core functionality from a relatively lean scene graph abstraction layer. Thus, the framework features different scene graph APIs, in particular OpenSG and Cosmo3D. Using our framework manipulation functionality can be easily integrated into any existing application since it only introduces a few new objects that have to be connected to the application. Our framework provides different manipulators for selection, scaling, rotation, and translation of objects. Moreover a set of editors allows for the manipulation of light and material properties. We demonstrate the extensibility of our framework both, in terms of customized manipulators and porting the framework to new scene graph APIs, which is supported by a clear object-oriented structure.
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    TRIPS - A Scalable Spatial Sound Library for OpenSG
    (The Eurographics Association, 2003) Neumann, Tomas; Fünfzig, Christoph; Fellner, Dieter W.; Dirk Reiners
    We present a Sound Library that is scalable on several computers and that brings the idea of a self-organized scenegraph to the Sound Library's interface. It supports the implementation of audio features right from the start at a high productivity level for rapid prototypes as well as for professional applications in the immersive domain. The system is built on top of OpenSG12 which offers a high level of functionality for visual applications and research, but does not come with audio support.We show and compare the effort to implement audio in an OpenSG application with and without TRIPS. Today's audio systems only accept raw 3D-coordinates and are limited to run on the same computer and the same operating system than the application runs on. Breaking these constraints could give developersmore freedom and ease to add high-quality spatial sound to their software. Therefore, users benefit from the promising potential OpenSG offers.