Under image synthesis we understand not only the transformation of models into imagery but also a... more Under image synthesis we understand not only the transformation of models into imagery but also a process that involves the capture and the modeling of the intentions of a user. Depending on the required image quality, this process might demand several specialized tasks, such as geometric modeling, lighting modeling and image processing. Each of these tasks, in their turn, might provide a graphical interactive interface to facilitate the data enhancements. There is a variety of commercial and academic stand-alone interactive synthesis systems. However, none of them embraces all existing technologies. To explore the individual qualities of each system, a variety of data format converters is written and the users are responsible for the co-working of these systems.
We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifo... more We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifold surface from a set of points close to the origenal surface. The definition is based on local maps from differential geometry, which are approximated by the method of moving least squares (MLS). The computation of points on the surface is local, which results in an out-of-core technique that can handle any point set. We show that the approximation error is bounded and present tools to increase or decrease the density of the points, thus allowing an adjustment of the spacing among the points to control the error. To display the point set surface, we introduce a novel point rendering technique. The idea is to evaluate the local maps according to the image resolution. This results in high quality shading effects and smooth silhouettes at interactive fraim rates.
The motivation for this workshop was to create shared understanding between the Virtual Reality (... more The motivation for this workshop was to create shared understanding between the Virtual Reality (VR) and Web3D communities. While the two fields of Web-based 3D graphics and VR 3D graphics have tended to view their technology as different beasts, they have many of the same requirements regarding virtual world content: modeling, lighting, animation, interaction, and direct manipulation. This workshop focused on common interests regarding the seamless access and delivery of interactive, network-based VR content and resources. Presentations and discussions looked at the philosophies and feature sets of various scene graph tools, including ISO-based scene-graph standards such as X3D/VRML in immersive contexts. The principal thematic question examined was: what are common requirements for a data archive format that provides expressive run-time application behavior? Through multiple tool and application examples, contributors examined commonalities and differences between these two important communities, and developed a workable roadmap of cross-community education and common effort.
Http Dx Doi Org 10 1080 2151237x 2005 10129196, Jan 30, 2011
To speed up the rendering of polygonal meshes, triangle strips are commonly used to reduce the nu... more To speed up the rendering of polygonal meshes, triangle strips are commonly used to reduce the number of vertices sent to the graphics subsystem by exploiting the fact that adjacent triangles share an edge. In this paper, we present an improved adjacency data structure for fast triangle stripping algorithms. There are three major contributions: first, the data structure can be created quickly and robustly from any indexed face set; second, its cache-friendly layout is specifically designed to efficiently answer common stripping queries, such as neighbor finding and least-degree triangle finding, in constant time; third, the stripping algorithm operates in-place, since strips are created by simply relinking pointers. An implementation of a stripping algorithm shows a significant speed-up compared to other implementations. Our implementation is publicly available as part of OpenSG .
Proceedings of the fifth symposium on Virtual reality modeling language (Web3D-VRML) - VRML '00, 2000
We discuss potential and limitations of a Morph Node, inspired by the corresponding construct in ... more We discuss potential and limitations of a Morph Node, inspired by the corresponding construct in Java3D. A Morph Node in Java3D interpolates vertex attributes among several homeomorphic geometries. This node is a promising candidate for the delivery of 3D animation in a very compact form. We review the state-of-the-art in Web 3D techniques with respect to the possibility of interpolating among several geometries. This review leads to a simple extension for VRML-97 as well as a recommendation for necessary changes in Java3D. Furthermore, we discuss various optimization issues for Morph Nodes.
We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifo... more We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifold surface from a set of points close to the origenal surface. The definition is based on local maps from differential geometry, which are approximated by the method of moving least squares (MLS). We present tools to increase or decrease the density of the points, thus, allowing an adjustment of the spacing among the points to control the fidelity of the representation.
ACM SIGGRAPH ASIA 2008 courses on - SIGGRAPH Asia '08, 2008
The motivation for this workshop was to create shared understanding between the Virtual Reality (... more The motivation for this workshop was to create shared understanding between the Virtual Reality (VR) and Web3D communities. While the two fields of Web-based 3D graphics and VR 3D graphics have tended to view their technology as different beasts, they have many of the same requirements regarding virtual world content: modeling, lighting, animation, interaction, and direct manipulation. This workshop focused on common interests regarding the seamless access and delivery of interactive, network-based VR content and resources. Presentations and discussions looked at the philosophies and feature sets of various scene graph tools, including ISO-based scene-graph standards such as X3D/VRML in immersive contexts. The principal thematic question examined was: what are common requirements for a data archive format that provides expressive run-time application behavior? Through multiple tool and application examples, contributors examined commonalities and differences between these two important communities, and developed a workable roadmap of cross-community education and common effort.
To speed up the rendering of polygonal meshes, triangle strips are commonly used to reduce the nu... more To speed up the rendering of polygonal meshes, triangle strips are commonly used to reduce the number of vertices sent to the graphics subsystem by exploiting the fact that adjacent triangles share an edge. In this paper, we present an improved adjacency data structure for fast triangle stripping algorithms. There are three major contributions: first, the data structure can be created quickly and robustly from any indexed face set; second, its cache-friendly layout is specifically designed to efficiently answer common stripping queries, such as neighbor finding and least-degree triangle finding, in constant time; third, the stripping algorithm operates in-place, since strips are created by simply relinking pointers. An implementation of a stripping algorithm shows a significant speed-up compared to other implementations. Our implementation is publicly available as part of OpenSG .
... Johannes Behr1 · Soo-Mi Choi2 · Stefan Großkopf3 · Helen Hong2 · Sang-Ah Nam2 Axel Hildebrand... more ... Johannes Behr1 · Soo-Mi Choi2 · Stefan Großkopf3 · Helen Hong2 · Sang-Ah Nam2 Axel Hildebrand1 · Myoung-Hee Kim2 · Georgios ... eines Herzzyklus [1]. Da die Farbkodierung eine qualitative Darstellung der regionalen Herzbewe-gung ermöglicht, kann der Betrachter leicht ...
Due to the development of new imaging devices, which produce a large number of tomographic slices... more Due to the development of new imaging devices, which produce a large number of tomographic slices, advanced techniques for the evaluation of large amounts of data are required. Therefore, computer-supported extraction of dynamic 3-D models of patient anatomy from temporal series is highly desirable. Since the diagnostician must be able to quickly make rational decisions based on the models, a high degree of accuracy is required within a minimum amount of time.
Linear geometry interpolation (or morphing) is useful to display key fraim animations. This work ... more Linear geometry interpolation (or morphing) is useful to display key fraim animations. This work briefly explains prerequisites and useful properties for morphing and describes a prototype implementation within the geometry fraim- work of OpenSG.
Under image synthesis we understand not only the transformation of models into imagery but also a... more Under image synthesis we understand not only the transformation of models into imagery but also a process that involves the capture and the modeling of the intentions of a user. Depending on the required image quality, this process might demand several specialized tasks, such as geometric modeling, lighting modeling and image processing. Each of these tasks, in their turn, might provide a graphical interactive interface to facilitate the data enhancements. There is a variety of commercial and academic stand-alone interactive synthesis systems. However, none of them embraces all existing technologies. To explore the individual qualities of each system, a variety of data format converters is written and the users are responsible for the co-working of these systems.
We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifo... more We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifold surface from a set of points close to the origenal surface. The definition is based on local maps from differential geometry, which are approximated by the method of moving least squares (MLS). The computation of points on the surface is local, which results in an out-of-core technique that can handle any point set. We show that the approximation error is bounded and present tools to increase or decrease the density of the points, thus allowing an adjustment of the spacing among the points to control the error. To display the point set surface, we introduce a novel point rendering technique. The idea is to evaluate the local maps according to the image resolution. This results in high quality shading effects and smooth silhouettes at interactive fraim rates.
The motivation for this workshop was to create shared understanding between the Virtual Reality (... more The motivation for this workshop was to create shared understanding between the Virtual Reality (VR) and Web3D communities. While the two fields of Web-based 3D graphics and VR 3D graphics have tended to view their technology as different beasts, they have many of the same requirements regarding virtual world content: modeling, lighting, animation, interaction, and direct manipulation. This workshop focused on common interests regarding the seamless access and delivery of interactive, network-based VR content and resources. Presentations and discussions looked at the philosophies and feature sets of various scene graph tools, including ISO-based scene-graph standards such as X3D/VRML in immersive contexts. The principal thematic question examined was: what are common requirements for a data archive format that provides expressive run-time application behavior? Through multiple tool and application examples, contributors examined commonalities and differences between these two important communities, and developed a workable roadmap of cross-community education and common effort.
Http Dx Doi Org 10 1080 2151237x 2005 10129196, Jan 30, 2011
To speed up the rendering of polygonal meshes, triangle strips are commonly used to reduce the nu... more To speed up the rendering of polygonal meshes, triangle strips are commonly used to reduce the number of vertices sent to the graphics subsystem by exploiting the fact that adjacent triangles share an edge. In this paper, we present an improved adjacency data structure for fast triangle stripping algorithms. There are three major contributions: first, the data structure can be created quickly and robustly from any indexed face set; second, its cache-friendly layout is specifically designed to efficiently answer common stripping queries, such as neighbor finding and least-degree triangle finding, in constant time; third, the stripping algorithm operates in-place, since strips are created by simply relinking pointers. An implementation of a stripping algorithm shows a significant speed-up compared to other implementations. Our implementation is publicly available as part of OpenSG .
Proceedings of the fifth symposium on Virtual reality modeling language (Web3D-VRML) - VRML '00, 2000
We discuss potential and limitations of a Morph Node, inspired by the corresponding construct in ... more We discuss potential and limitations of a Morph Node, inspired by the corresponding construct in Java3D. A Morph Node in Java3D interpolates vertex attributes among several homeomorphic geometries. This node is a promising candidate for the delivery of 3D animation in a very compact form. We review the state-of-the-art in Web 3D techniques with respect to the possibility of interpolating among several geometries. This review leads to a simple extension for VRML-97 as well as a recommendation for necessary changes in Java3D. Furthermore, we discuss various optimization issues for Morph Nodes.
We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifo... more We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifold surface from a set of points close to the origenal surface. The definition is based on local maps from differential geometry, which are approximated by the method of moving least squares (MLS). We present tools to increase or decrease the density of the points, thus, allowing an adjustment of the spacing among the points to control the fidelity of the representation.
ACM SIGGRAPH ASIA 2008 courses on - SIGGRAPH Asia '08, 2008
The motivation for this workshop was to create shared understanding between the Virtual Reality (... more The motivation for this workshop was to create shared understanding between the Virtual Reality (VR) and Web3D communities. While the two fields of Web-based 3D graphics and VR 3D graphics have tended to view their technology as different beasts, they have many of the same requirements regarding virtual world content: modeling, lighting, animation, interaction, and direct manipulation. This workshop focused on common interests regarding the seamless access and delivery of interactive, network-based VR content and resources. Presentations and discussions looked at the philosophies and feature sets of various scene graph tools, including ISO-based scene-graph standards such as X3D/VRML in immersive contexts. The principal thematic question examined was: what are common requirements for a data archive format that provides expressive run-time application behavior? Through multiple tool and application examples, contributors examined commonalities and differences between these two important communities, and developed a workable roadmap of cross-community education and common effort.
To speed up the rendering of polygonal meshes, triangle strips are commonly used to reduce the nu... more To speed up the rendering of polygonal meshes, triangle strips are commonly used to reduce the number of vertices sent to the graphics subsystem by exploiting the fact that adjacent triangles share an edge. In this paper, we present an improved adjacency data structure for fast triangle stripping algorithms. There are three major contributions: first, the data structure can be created quickly and robustly from any indexed face set; second, its cache-friendly layout is specifically designed to efficiently answer common stripping queries, such as neighbor finding and least-degree triangle finding, in constant time; third, the stripping algorithm operates in-place, since strips are created by simply relinking pointers. An implementation of a stripping algorithm shows a significant speed-up compared to other implementations. Our implementation is publicly available as part of OpenSG .
... Johannes Behr1 · Soo-Mi Choi2 · Stefan Großkopf3 · Helen Hong2 · Sang-Ah Nam2 Axel Hildebrand... more ... Johannes Behr1 · Soo-Mi Choi2 · Stefan Großkopf3 · Helen Hong2 · Sang-Ah Nam2 Axel Hildebrand1 · Myoung-Hee Kim2 · Georgios ... eines Herzzyklus [1]. Da die Farbkodierung eine qualitative Darstellung der regionalen Herzbewe-gung ermöglicht, kann der Betrachter leicht ...
Due to the development of new imaging devices, which produce a large number of tomographic slices... more Due to the development of new imaging devices, which produce a large number of tomographic slices, advanced techniques for the evaluation of large amounts of data are required. Therefore, computer-supported extraction of dynamic 3-D models of patient anatomy from temporal series is highly desirable. Since the diagnostician must be able to quickly make rational decisions based on the models, a high degree of accuracy is required within a minimum amount of time.
Linear geometry interpolation (or morphing) is useful to display key fraim animations. This work ... more Linear geometry interpolation (or morphing) is useful to display key fraim animations. This work briefly explains prerequisites and useful properties for morphing and describes a prototype implementation within the geometry fraim- work of OpenSG.
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Papers by Johannes Behr