The blue-c Distributed Scene Graph

In this paper we present a distributed scene graph architecture for use in the blue-c, a novel collaborative immersive virtual environment. We extend the widely used OpenGL Performer toolkit to provide a distributed scene graph maintaining full synchronization down to vertex and texel level. We propose a synchronization scheme including customizable, relaxed locking mechanisms. We demonstrate the functionality of our toolkit with two prototype applications in our high-performance virtual reality and visual simulation environment

Stride scheduling for time-critical collision detection

We present an event-based scheduling method for time-critical collision detection that meets real-time constraints by balancing and prioritizing computation spent on inter-section tests without starvation. We test each potentially colliding pair of objects at a different frequency, with un-bounded temporal resolution. We show that believability is preserved by adaptively prioritizing intersection tests to re-duce errors in collision detection, using information about the objects and scene. Through the combination of kinetic sweep and prune with stride scheduling we continuously interleave rendering, broad phase collision pruning, nar-row phase intersection testing, and collision response. Our method accrues no per-frame overhead and is interruptible at any point in collision detection, even the broad phase.

Multiresolution Surface and Volume Representations

We present a wavelet-based geometry compression pipeline in the context of hierarchical surface and volume representations. Due to the increasing complexity of geometric models used in a vast number of different application field, new methods have to be devised that enable one to store, transmit and manipulate large amounts of data. Based on a multiresolution wavelet representation, we have developed a complete compression pipeline suitable for geometric data on uniform grids in two and three dimensions. Local and global oracles in wavelet space are employed to control the approximation error in lossy compression settings. Two geometry simplification schemes, which are able to build hierarchical mesh representations, are an essential part of the pipeline. In contrast to the two wavelet-based approximation schemes with each other using several two- and three-dimensional data sets and provide an extensive error and performance analysis. These results emphasize the individual strengths and weaknesses of each of the discussed methods and concepts

Multiresolution Surface and Volume Representations

We present a wavelet-based geometry compression pipeline in the context of hierarchical surface and volume representations. Due to the increasing complexity of geometric models used in a vast number of different application fields, new methods have to be devised that enable one to store, transmit and manipulate large amounts of data. Based on a multiresolution wavelet representation, we have developed a complete compression pipeline suitable for geometric data on uniform grids in two and three dimensions. Local and global oracles in wavelet space are employed to control the approximation error in lossy compression settings. Two geometry simplification schemes, which are able to build hierarchical mesh representations, are an essential part of the pipeline. In contrast to the two wavelet-based approximation schemes, we have devised the progressive tetrahedralization method, an extension of the popular progressive meshes into volumetric settings. We compare the three approximation schemes with each other using several two- and three-dimensional data sets and provide an extensive error and performance analysis. These results emphasize the individual strengths and weaknesses of each of the discussed methods and concepts

Progressive Tetrahedralizations

This paper describes some fundamental issues for robust implementations of progressively refined tetrahedralizations generated through sequences of edge collapses. We address the definition of appropriate cost functions and explain on various tests which are necessary to preserve the consistency of the mesh when collapsing edges. Although being considered a special case of progressive simplicial complexes [10], the results of our method are of high practical importance and can be used in many different applications, such as finite element meshing, scattered data interpolation, or rendering of unstructured volume data

Progressive Tetrahedralizations

This paper describes some fundamental issues for robust implementations of progressively refined tetrahedralizations generated through sequences of edge collapses. We address the definition of appropriate cost functions and explain on various tests which are necessary to preserve the consistency of the mesh when collapsing edges. Although being considered a special case of progressive simplicial complexes [10], the results of our method are of high practical importance and can be used in many different applications, such as finite element meshing, scattered data interpolation, or rendering of unstructured volume data. CR Categories: I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling -- surfaces and object representations. Keywords: mesh simplification, multiresolution, level-ofdetail, unstructured meshes, mesh generation. 1 INTRODUCTION Progressive meshes [7] and its generalizations to higher dimensions [10] proofed to be an extremely powerful notion for the effic..

Avoiding Errors in Progressive Tetrahedralizations

This paper describes some fundamental issues for robust implementations of progressively refined tetrahedralizations generated through sequences of edge collapses. We address the definition of appropriate cost functions and explain on various tests which are necessary to preserve the consistency of the mesh when collapsing edges. Although being considered a special case of progressive simplicial complexes [4], the results of our method are of high practical importance and can be used in many different applications, such as finite element meshing, scattered data interpolation or rendering of irregular volume data. CR Categories: I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling -- surfaces and object representations. Keywords: mesh simplification, multiresolution, FEM meshing. 1 INTRODUCTION Progressive meshes [3] and its generalizations to higher dimensions [4] have proofed to be an extremely powerful notion for the efficient representation of triangulated geome..

Kinetic Sweep and Prune for Collision Detection

We propose an acceleration scheme for real-time many-body dynamic collision detection. We kinetize the sweep and prune method for many-body collision pruning, extending its application to dynamic collision detection via kinetic data structures. In doing so, we modify the method from sample-rate driven to event-driven, with no more events than the original method processed, also removing the per-frame overhead, allowing our method to scale well in terms of frame-rates. Unlike many schemes for many-body collision pruning, ours performs well in both sparse and dense environments, with few or many collisions. Categories and Subject Descriptors (according to ACM CCS): I.3.6 [Computer Graphics]: Methodology and Techniques—Graphics data structures and data types; I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Virtual realit