@mastersthesis{LEHNINGER-2007-SSV, title = "Simulation von st\"{a}dtischem Verkehr", author = "Gregor Lehninger", year = "2007", abstract = "The task of this thesis is the simulation of urban traffic. For this purpose the traffic library TrafLib was developed. TrafLib is a multi-agent, micro simulation for urban traffic. It is suitable for visualisation, e.g. urban visualisation software, driving simulators, computer games, virtual reality software, and so on. It enhances them and makes them more attractive. TrafLib requires a road-network in the form of an input file. The input file must contain the description of roads and crossings, and optionally traffic lights and traffic signs. Additionally to the own file description format, the format of VRMG is also supported. VRMG is a program for creating geometry of large road-networks. The problem of traffic calculation is solved by handling traffic rules according to the Highway Code and the “Car-Following-Theory”. The vehicles are modelled as autonomous agents. Human characteristics are imitated by three different types of driving-behaviour (cautious, normal, aggressive). The movement of the vehicles takes place on 1-dimensional lanes. This reduces the flexibility a little, but simplifies the calculation a lot. TrafLib is able to simulate more than 5000 vehicles on a road network of the size of 3 times 3 km in real-time on a standard-PC.", month = apr, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "traffic simulation, real-time rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/LEHNINGER-2007-SSV/", } @inproceedings{bittner-2005-egsr, title = "Fast Exact From-Region Visibility in Urban Scenes", author = "Jir\'{i} Bittner and Peter Wonka and Michael Wimmer", year = "2005", abstract = "We present a fast exact from-region visibility algorithm for 2.5D urban scenes. The algorithm uses a hierarchical subdivision of line-space for identifying visibility interactions in a 2D footprint of the scene. Visibility in the remaining vertical dimension is resolved by testing for the existence of lines stabbing sequences of virtual portals. Our results show that exact analytic from-region visibility in urban scenes can be computed at times comparable or even superior to recent conservative methods. ", month = jun, isbn = "3-905673-23-1", publisher = "Eurographics Association", organization = "Eurographics", location = "Konstanz, Germany", editor = "Kavita Bala and Philip Dutr\'{e}", booktitle = "Rendering Techniques 2005 (Proceedings Eurographics Symposium on Rendering)", pages = "223--230", keywords = "real-time rendering, visibility", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/bittner-2005-egsr/", } @article{Bittner-2004-CHC, title = "Coherent Hierarchical Culling: Hardware Occlusion Queries Made Useful", author = "Jir\'{i} Bittner and Michael Wimmer and Harald Piringer and Werner Purgathofer", year = "2004", abstract = "We present a simple but powerful algorithm for optimizing the usage of hardware occlusion queries in arbitrary complex scenes. Our method minimizes the number of issued queries and reduces the delays due to the latency of query results. We reuse the results of the occlusion queries from the last frame in order to initiate and schedule the queries in the next frame. This is done by processing nodes of a spatial hierarchy in front-to-back order, interleaving occlusion queries with the rendering of certain previously visible nodes. The proposed scheduling of the queries makes use of spatial and temporal coherence of visibility. Despite its simplicity, the algorithm achieves good culling efficiency for scenes of various characteristics. The implementation of the algorithm is straightforward, and it can be easily integrated in existing real-time rendering packages using various spatial data structures.", month = sep, journal = "Computer Graphics Forum", volume = "23", number = "3", note = "Proceedings EUROGRAPHICS 2004", issn = "0167-7055", pages = "615--624", keywords = "occlusion query, visibility, real-time rendering, occlusion culling", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/Bittner-2004-CHC/", } @inproceedings{Wimmer-2004-LSPM, title = "Light Space Perspective Shadow Maps", author = "Michael Wimmer and Daniel Scherzer and Werner Purgathofer", year = "2004", abstract = "In this paper, we present a new shadow mapping technique that improves the quality of perspective and uniform shadow maps. Our technique uses a perspective transform specified in light space which allows treating all lights as directional lights and does not change the direction of the light sources. This gives all the benefits of the perspective mapping but avoids the problems inherent in perspective shadow mapping like singularities in post-perspective space, missed shadow casters etc. Furthermore, we show that both uniform and perspective shadow maps distribute the perspective aliasing error that occurs in shadow mapping unequally over the available z-range. We therefore propose a transform that equalizes this error and gives equally pleasing results for near and far viewing distances. Our method is simple to implement, requires no scene analysis and is therefore as fast as uniform shadow mapping.", month = jun, isbn = "3-905673-12-6", publisher = "Eurographics Association", organization = "Eurographics", location = "Norrk\"{o}ping, Sweden", editor = "Alexander Keller and Henrik W. Jensen", booktitle = "Rendering Techniques 2004 (Proceedings Eurographics Symposium on Rendering)", pages = "143--151", keywords = "shadows, real-time rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/Wimmer-2004-LSPM/", } @article{Bittner-2003-Vis, title = "Visibility in Computer Graphics", author = "Jir\'{i} Bittner and Peter Wonka", year = "2003", abstract = "Visibility computation is crucial for computer graphics from its very beginning. The first visibility algorithms in computer graphics aimed to determine visible surfaces in a synthesized image of a 3D scene. Nowadays there are many different visibility algorithms for various visibility problems. We propose a new taxonomy of visibility problems that is based on a classification according to the problem domain. We provide a broad overview of visibility problems and algorithms in computer graphics grouped by the proposed taxonomy. The paper surveys visible surface algorithms, visibility culling algorithms, visibility algorithms for shadow computation, global illumination, point-based and image-based rendering, and global visibility computations. Finally, we discuss common concepts of visibility algorithm design and several criteria for the classification of visibility algorithms.", month = sep, issn = "0265-8135", journal = "Environment and Planning B: Planning and Design", number = "5", volume = "30", pages = "729--756", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Bittner-2003-Vis/", } @article{Wonka-2003-Ins, title = "Instant Architecture", author = "Peter Wonka and Michael Wimmer and Fran\c{c}ois Sillion and William Ribarsky", year = "2003", abstract = "This paper presents a new method for the automatic modeling of architecture. Building designs are derived using split grammars, a new type of parametric set grammar based on the concept of shape. The paper also introduces an attribute matching system and a separate control grammar, which offer the flexibility required to model buildings using a large variety of different styles and design ideas. Through the adaptive nature of the design grammar used, the created building designs can either be generic or adhere closely to a specified goal, depending on the amount of data available.", month = jul, journal = "ACM Transaction on Graphics", volume = "22", number = "3", note = "Proceedings ACM SIGGRAPH 2003", issn = "0730-0301", doi = "10.1145/882262.882324", pages = "669--677", keywords = "architecture, shape grammars, urban environments, modeling, real-time simulation, building design", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Wonka-2003-Ins/", } @mastersthesis{PIRINGER-2003-HBOQ, title = "Occlusion Culling Using Hardware-Based Occlusion Queries", author = "Harald Piringer", year = "2003", abstract = "Today, a major challenge of computer graphics is the generation of realistic images at rates that arouse the impression of fluid motion in the viewer. Of central importance in this context is the application of specialized hardware, which has experienced an impressive evolution in recent years, increasing both speed and functionality in a significant fashion. However, displaying complex scenes like whole cities requires dealing with such an amount of data, that dedicated acceleration algorithms are still necessary in order to cope with the tight temporal constraints. In doing so, methods for detecting invisible parts of the scenery play a key role. A particular challenge is classifying those objects in an efficient way which are invisible due to being entirely occluded by other objects in front of them. Although this visibility problem belongs to the classical tasks of computer graphics, just recently introduced extensions to the graphics hardware permit the design of new algorithms with fascinating opportunities, but also requirements that have been of no concern to previous approaches. This master thesis deals with the task of developing an efficient algorithm for solving the visibility problem for arbitrary scenes, which is tailored towards the NV_occlusion_query OpenGL extension, in different ways: One method approximates the potential occlusion within a given scenery from a certain viewpoint by constructing a directed acyclic graph, which is in turn used to be able to issue as many occlusion queries as possible in a concurrent fashion. Several extensions amend and improve the core algorithm by employing a more equal load balancing and exploiting both temporal and spatial coherence. Finally, this approach is extended by incorporating an appropriate spatial hierarchy. Although this technique is by and large significantly superior to rendering without occlusion culling, the obtained results are not satisfactory in every respect. Therefore, a second approach is proposed that does not rely on any graph. This hierarchical algorithm depends entirely on the visibility classification of previous frames and stresses thus the aspect of temporal coherence. Even though it is considerably simpler than the first approach, it yields superior and generally convincing results. Both approaches are conservative (which means that they do not affect the correctness of the resulting image), but can easily be modified in a way that permits to trade off quality for speed by tolerating precisely definable mistakes.", month = jul, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "real-time rendering, occlusion queries, occlusion culling", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/PIRINGER-2003-HBOQ/", } @inproceedings{Wimmer-2003-RTE, title = "Rendering Time Estimation for Real-Time Rendering", author = "Michael Wimmer and Peter Wonka", year = "2003", abstract = "This paper addresses the problem of estimating the rendering time for a real-time simulation. We study different factors that contribute to the rendering time in order to develop a framework for rendering time estimation. Given a viewpoint (or view cell) and a list of potentially visible objects, we propose several algorithms that can give reasonable upper limits for the rendering time on consumer hardware. This paper also discusses several implementation issues and design choices that are necessary to make the rendering time predictable. Finally, we lay out two extensions to current rendering hardware which would allow implementing a system with constant frame rates.", month = jun, isbn = "3-905673-03-7", publisher = "Eurographics Association", organization = "Eurographics", location = "Leuven, Belgium", editor = "Per Christensen and Daniel Cohen-Or", booktitle = "Rendering Techniques 2003 (Proceedings Eurographics Symposium on Rendering)", pages = "118--129", keywords = "graphics hardware, real-time rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Wimmer-2003-RTE/", } @inproceedings{Jeschke-2002-TDMR, title = "Textured Depth Meshes for Real-Time Rendering of Arbitrary Scenes", author = "Stefan Jeschke and Michael Wimmer", year = "2002", abstract = "This paper presents a new approach to generate textured depth meshes (TDMs), an impostor-based scene representation that can be used to accelerate the rendering of static polygonal models. The TDMs are precalculated for a fixed viewing region (view cell). The approach relies on a layered rendering of the scene to produce a voxel-based representation. Secondary, a highly complex polygon mesh is constructed that covers all the voxels. Afterwards, this mesh is simplified using a special error metric to ensure that all voxels stay covered. Finally, the remaining polygons are resampled using the voxel representation to obtain their textures. The contribution of our approach is manifold: first, it can handle polygonal models without any knowledge about their structure. Second, only scene parts that may become visible from within the view cell are represented, thereby cutting down on impostor complexity and storage costs. Third, an error metric guarantees that the impostors are practically indistinguishable compared to the original model (i.e. no rubber-sheet effects or holes appear as in most previous approaches). Furthermore, current graphics hardware is exploited for the construction and use of the impostors.", month = jun, isbn = "1-58133-534-3", publisher = "Eurographics Association", organization = "Eurographics", location = "Pisa, Italy", editor = "Paul Debevec and Simon Gibson", booktitle = "Rendering Techniques 2002 (Proceedings Eurographics Workshop on Rendering)", pages = "181--190", keywords = "Rendering, Walkthrough, Computer Graphics, Impostors", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Jeschke-2002-TDMR/", } @inproceedings{Jeschke-2002-LEMA, title = "Layered Environment-Map Impostors for Arbitrary Scenes", author = "Stefan Jeschke and Michael Wimmer and Heidrun Schumann", year = "2002", abstract = "This paper presents a new impostor-based approach to accelerate the rendering of very complex static scenes. The scene is partitioned into viewing regions, and a layered impostor representation is precalculated for each of them. An optimal placement of impostor layers guarantees that our representation is indistinguishable from the original geometry. Furthermore the algorithm exploits common graphics hardware both during preprocessing and rendering. Moreover the impostor representation is compressed using several strategies to cut down on storage space.", month = may, isbn = "1-56881-183-7", publisher = "AK Peters Ltd.", location = "Calgary, CA", editor = "Wolfgang St\"{u}rzlinger and Michael McCool", booktitle = "Proceedings of Graphics Interface 2002", pages = "1--8", keywords = "virtual environments, environment maps, impostors, walkthroughs, image-based rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Jeschke-2002-LEMA/", } @techreport{TR-186-2-02-04, title = "An Error Metric for Layered Environment Map Impostors", author = "Stefan Jeschke and Michael Wimmer", year = "2002", abstract = "Impostors are image-based primitives commonly used to replace complex geometry in order to accelerate the rendering of large virtual environments. This paper describes a “layered impostor technique” used for representing distant scene-parts when seen from a bounded viewing region. A special layer placement is derived which bounds the geometric error introduced by parallaxes to a defined value. In combination with a special technique for image generation, a high-quality impostor representation without image artifacts can be obtained.", month = feb, number = "TR-186-2-02-04", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "impostors, real-time rendering, virtual", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/TR-186-2-02-04/", } @inproceedings{Bittner-2001-Vis, title = "Visibility Preprocessing for Urban Scenes using Line Space Subdivision", author = "Jir\'{i} Bittner and Peter Wonka and Michael Wimmer", year = "2001", abstract = "We present an algorithm for visibility preprocessing of urban environments. The algorithm uses a subdivision of line space to analytically calculate a conservative potentially visible set for a given region in the scene. We present a detailed evaluation of our method including a comparison to another recently published visibility preprocessing algorithm. To the best of our knowledge the proposed method is the first algorithm that scales to large scenes and efficiently handles large view cells.", month = oct, isbn = "0-7695-1227-5", publisher = "IEEE Computer Society Press", location = "Tokyo, Japan", editor = "Bob Werner", booktitle = "Proceedings of Pacific Graphics 2001 (Ninth Pacific Conference on Computer Graphics and Applications)", pages = "276--284", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Bittner-2001-Vis/", } @article{Wonka-2001-Ins, title = "Instant Visibility", author = "Peter Wonka and Michael Wimmer and Fran\c{c}ois Sillion", year = "2001", abstract = "We present an online occlusion culling system which computes visibility in parallel to the rendering pipeline. We show how to use point visibility algorithms to quickly calculate a tight potentially visible set (PVS) which is valid for several frames, by shrinking the occluders used in visibility calculations by an adequate amount. These visibility calculations can be performed on a visibility server, possibly a distinct computer communicating with the display host over a local network. The resulting system essentially combines the advantages of online visibility processing and region-based visibility calculations, allowing asynchronous processing of visibility and display operations. We analyze two different types of hardware-based point visibility algorithms and address the problem of bounded calculation time which is the basis for true real-time behavior. Our results show reliable, sustained 60 Hz performance in a walkthrough with an urban environment of nearly 2 million polygons, and a terrain flyover.", month = sep, journal = "Computer Graphics Forum", volume = "20", number = "3", note = "G\"{u}nther Enderle [Best Paper] Award, Best Student Paper Award. A. Chalmers and T.-M. Rhyne (eds.), Proceedings EUROGRAPHICS 2001", issn = "0167-7055", pages = "411--421", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Wonka-2001-Ins/", } @inproceedings{Wimmer-2001-Poi, title = "Point-Based Impostors for Real-Time Visualization", author = "Michael Wimmer and Peter Wonka and Fran\c{c}ois Sillion", year = "2001", abstract = "We present a new data structure for encoding the appearance of a geometric model as seen from a viewing region (view cell). This representation can be used in interactive or real-time visualization applications to replace a complex model by an impostor, maintaining high quality rendering while cutting down rendering time. Our approach relies on an object-space sampled representation similar to a point cloud or a layered depth image, but introduces two fundamental additions to previous techniques. First, the sampling rate is controlled to provide sufficient density across all possible viewing conditions from the specified view cell. Second, a correct, antialiased representation of the plenoptic function is computed using Monte Carlo integration. Our system therefore achieves high quality rendering using a simple representation with bounded complexity. We demonstrate the method for an application in urban visualization.", month = jun, isbn = "3-211-83709-4", publisher = "Springer-Verlag", organization = "Eurographics", editor = "Steven J. Gortler and Karol Myszkowski", booktitle = "Rendering Techniques 2001 (Proceedings Eurographics Workshop on Rendering)", pages = "163--176", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Wimmer-2001-Poi/", } @mastersthesis{HUMMEL-2001-MSE, title = "Modellierung von Stra{\ss}en f\"{u}r Echtzeitvisualisierung", author = "Gerald Hummel", year = "2001", abstract = "Diese Diplomarbeit ist die theoretische Abhandlung von VRMG, einem Softwareprojekt, das im Rahmen des praktischen Teiles der Arbeit realisiert wurde und die Modellierung von Terrain und Stra{\ss}en virtueller St\"{a}dte zum Zwecke der Echzeit-Visualisierung bewerkstelligt. Ausgehend von den Vermessungsdaten in Form von geografischen H\"{o}henwerten und dem Stra{\ss}ennetz, das als Stra{\ss}engraph vorliegt, werden alle Schritte zur Umsetzung dieser Rohdaten in Geometriedaten f\"{u}r die separate Modellerstellung des Terrains und der Stra{\ss}enz\"{u}ge behandelt. Der Schwerpunkt der Arbeit liegt auf dem Anwendungsfall – Stadtstra{\ss}en. Somit umfa{\ss}t VRMG zahlreiche Elemente f\"{u}r den Aufbau von Stra{\ss}en, wie sie typischerweise im Stadtbereich zu finden sind. Dadurch ist es m\"{o}glich, zahlreiche Stra{\ss}en-Konfigurationen aus der Realit\"{a}t nachzubilden. Das Terrain wird als konventioneller, Regul\"{a}rer-Raster erfa{\ss}t. Nach der Berechnung der Stra{\ss}en- bzw. H\"{o}henfeldgeometrie, die auf Grundlage von Beschreibungsfiles zur Eingabe der spezifischen Parameter erfolgt, liegt das Ergebnis dieses Schrittes in polygonaler Repr\"{a}sentationsform vor. Dadurch, da{\ss} die Modell-Geometrie vorzugsweise f\"{u}r Echtzeitanwendungen eingesetzt wird, ist die Aufbereitung der polygonalen Repr\"{a}sentation durch Nachfolgeoperationen zur Optimierung der Geometrie bedeutsam. Durch die Verfahren der Delaunay-Triangulierung und des Triangle- Stripping werden die Polygone mittels Dreieckszerlegung tesseliert und dadurch in eine Form gebracht, die die derzeitigen 3D-Hardwarebeschleunigerchips unterst\"{u}tzen. Das endg\"{u}ltige Resultat wird als Szenegraph, der als Baumstruktur die Geometrie- und Texturierungdaten in hierarchischer Form aufnimmt, gespeichert und f\"{u}r die Verwendung, etwa als Simulationsumgebung, zur Verf\"{u}gung gestellt.", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/HUMMEL-2001-MSE/", } @inproceedings{wonka-2000-VisP, title = "Visibility Preprocessing with Occluder Fusion for Urban Walkthroughs", author = "Peter Wonka and Michael Wimmer and Dieter Schmalstieg", year = "2000", abstract = "This paper presents an efficient algorithm for occlusion culling of urban environments. It is conservative and accurate in finding all significant occlusion. It discretizes the scene into view cells, for which cell-to-object visibility is precomputed, making on-line overhead negligible. Unlike other precomputation methods for view cells, it is able to conservatively compute all forms of occluder interaction for an arbitrary number of occluders. To speed up preprocessing, standard graphics hardware is exploited and occluder occlusion is considered. A walkthrough application running an 8 million polygon model of the city of Vienna on consumer-level hardware illustrates our results.", month = jun, isbn = "3-211-83535-0", publisher = "Springer-Verlag Wien New York", organization = "Eurographics", location = "held in Brno, Czech Republic, June 26-28, 2000", editor = "Bernard P\'{e}roche and Holly Rushmeier", booktitle = "Rendering Techniques 2000 (Proceedings Eurographics Workshop on Rendering)", pages = "71--82", keywords = "Visibility determination, image-based rendering., occluder occlusion, occluder fusion, urban environments, walkthrough, real-time graphics, shadow algorithms, occlusion culling", URL = "https://www.cg.tuwien.ac.at/research/publications/2000/wonka-2000-VisP/", } @article{Wimmer-1999-FWIb, title = "Fast Walkthroughs with Image Caches and Ray Casting", author = "Michael Wimmer and Markus Giegl and Dieter Schmalstieg", year = "1999", abstract = "We present an output-sensitive rendering algorithm for accelerating walkthroughs of large, densely occluded virtual environments using a multi-stage Image Based Rendering Pipeline. In the first stage, objects within a certain distance are rendered using the traditional graphics pipeline, whereas the remaining scene is rendered by a pixel-based approach using an Image Cache, horizon estimation to avoid calculating sky pixels, and finally, ray casting. The time complexity of this approach does not depend on the total number of primitives in the scene. We have measured speedups of up to one oder of magnitude.", month = dec, issn = "0097-8493", journal = "Computers and Graphics", number = "6", volume = "23", pages = "831--838", URL = "https://www.cg.tuwien.ac.at/research/publications/1999/Wimmer-1999-FWIb/", } @inproceedings{Wimmer-1999-FWIa, title = "Fast Walkthroughs with Image Caches and Ray Casting", author = "Michael Wimmer and Markus Giegl and Dieter Schmalstieg", year = "1999", abstract = "We present an output-sensitive rendering algorithm for accelerating walkthroughs of large, densely occluded virtual environments using a multi-stage Image Based Rendering Pipeline. In the first stage, objects within a certain distance are rendered using the traditional graphics pipeline, whereas the remaining scene is rendered by a pixel-based approach using an Image Cache, horizon estimation to avoid calculating sky pixels, and finally, ray casting. The time complexity of this approach does not depend on the total number of primitives in the scene. We have measured speedups of up to one oder of magnitude.", month = jun, isbn = "3-211-83347-1", publisher = "Springer-Verlag Wien", organization = "Eurographics", editor = "Michael Gervautz and Dieter Schmalstieg and Axel Hildebrand", booktitle = "Virtual Environments '99. Proceedings of the 5th Eurographics Workshop on Virtual Environments", pages = "73--84", URL = "https://www.cg.tuwien.ac.at/research/publications/1999/Wimmer-1999-FWIa/", }