Publications

Thumbnail of In-Situ Comparison for 2.5D Treemaps

In-Situ Comparison for 2.5D Treemaps

Daniel Limberger, Matthias Trapp, and Jürgen Döllner
Proceedings of the International Conference on Information Visualization Theory and Applications 2019

Abstract |  Paper | Poster | Template Card

2.5D treemaps can be used to visualize tree-structured data using the height dimension for additional information display. For tree-structured and time-variant data though, changes or variants in the data are difficult to visualize. This paper presents an in-situ approach to depict differences between two versions (original and comparative state) of a data set, e.g., metrics of different revisions of a software system, in a single 2.5D treemap. Multiple geometry variants for the in-situ representation of individual nodes, especially concerning height, area, and color, are presented and discussed. Finally, a preliminary study for the simultaneous change of attributes in height and area is described, hinting that arrow pattern help to clarify reading direction.

Thumbnail of Interactive, Height-based Filtering in 2.5D Treemaps

Interactive, Height-based Filtering in 2.5D Treemaps

Daniel Limberger, Matthias Trapp, and Jürgen Döllner
Proceedings of the International Symposium on Visual Information Communication and Interaction 2018

Abstract |  BibTeX |  DOI | Paper | Slides

The 2.5D treemap facilitates interactive exploration of multivariate data. It includes height as a visual variable for additional information display and enables exploration of correlations within mapped attributes. In this paper techniques for the visual display of a height reference for interactive modification from within the visualization are introduced. Results of a preliminary user study are presented and potential benefits for improved performance, i.e., precision and speed, of identification, comparison, filtering, and selection tasks are discussed.

@inproceedings{limberger2018-reference, 
 author = {Limberger, Daniel and Trapp, Matthias and D\"{o}llner, J\"{u}rgen},
 title = {Interactive, Height-Based Filtering in 2.5D Treemaps},
 booktitle = {Proceedings of the 11th International Symposium on Visual Information Communication and Interaction},
 series = {VINCI '18},
 year = {2018},
 isbn = {978-1-4503-6501-7},
 location = {V\äxj\ö, Sweden},
 pages = {49--55},
 numpages = {7},
 url = {http://doi.acm.org/10.1145/3231622.3231638},
 doi = {10.1145/3231622.3231638},
 acmid = {3231638},
 publisher = {ACM},
 address = {New York, NY, USA},
 keywords = {Filtering, Height Cue, Height Reference, Selection, Treemap},
} 
Thumbnail of OpenLL: an API for Dynamic 2D and 3D Labeling

OpenLL: an API for Dynamic 2D and 3D Labeling

Daniel Limberger, Anne Gropler, Stefan Buschmann, Jürgen Döllner, and Benjamin Wasty
Proceedings of the International Conference on Information Visualization 2018

Abstract |  BibTeX |  DOI | Paper | Slides

Today's rendering APIs lack robust functionality and capabilities for dynamic, real-time text rendering and labeling, which represent key requirements for 3D application design in many fields. As a consequence, most rendering systems are barely or not at all equipped with respective capabilities. This paper drafts the unified text rendering and labeling API OpenLL intended to complement common rendering APIs, frameworks, and transmission formats. For it, various uses of static and dynamic placement of labels are showcased and a text interaction technique is presented. Furthermore, API design constraints with respect to state-of-the-art text rendering techniques are discussed. This contribution is intended to initiate a community-driven specification of a free and open label library.

@inproceedings{limberger2018-openll, 
 author = {Limberger, Daniel and Gropler, Anne and Buschmann, Stefan and Wasty, Benjamin and D\"{o}llner, J\"{u}rgen}, 
 booktitle = {2018 22nd International Conference Information Visualisation (IV)}, 
 title = {OpenLL: An API for Dynamic 2D and 3D Labeling}, 
 year = {2018}, 
 pages = {175-181}, 
 doi = {10.1109/iV.2018.00039}, 
 ISSN = {2375-0138}, 
 month = {July},
 keywords = {application program interfaces;data visualisation;human computer interaction;public domain software;rendering (computer graphics);text analysis;OpenLL;3D labeling;3D application design;free label library;open label library;API design;2D labeling;API rendering;text interaction;text rendering;Rendering (computer graphics);Labeling;Data visualization;Two dimensional displays;Three-dimensional displays;Real-time systems;Libraries;visualization;labeling;real-time rendering}, 
}
Thumbnail of Interactive, Adaptive Level-of-Detail in 2.5D Treemaps

Interactive, Adaptive Level-of-Detail in 2.5D Treemaps

Daniel Limberger
United States Patent and Trademark Office 2018

Abstract |  BibTeX |  Patent | USPTO

An aggregation approach allows for a dynamic, interactive, adaptive level-of-detail for 2D, 2.5D, and 3D treemaps for visualization of complex information. For example, the 2.5D treemap visualization concept is extended by providing adaptive identification of aggregates by means of an interactive node scoring approach based on contextual relevance and various other task, interaction, visibility, and/or performance specific criteria. For the resulting mapping and rendering, a per-frame aggregation of blocks and accumulation of those attributes mapped to visual variables (context) is described. Since every embodiment is also targeted for dynamic, interactive visual display of 2.5D treemaps, the rendering is designed to be capable for execution in real-time. Visual preservation of important information is conveyed by hierarchy elements and their mapped attributes (nodes-of-interest) as well as compliance to known aggregation guidelines including visualization of aggregated color and height information, visualization of aggregates that are discernible from non-aggregates, and visualization of outliers within aggregates. Applications include visualization of software maps, business intelligence data, file hierarchies for storage devices, and the like.

@misc{limberger2018-lod-treemaps,
 title = {Interactive, adaptive level-of-detail in 2.5 D treemaps},
 author = {Limberger, Daniel},
 year={2018},
 publisher = {Google Patents},
 note = {US Patent 9,953,443},
}
Thumbnail of Mixed-Projection Treemaps: A Novel Approach Mixing 2D and 2.5D Treemaps

Mixed-Projection Treemaps: A Novel Approach Mixing 2D and 2.5D Treemaps

Daniel Limberger, Willy Scheibel, Matthias Trapp, and Jürgen Döllner
Proceedings of the International Conference on Information Visualization 2017

Abstract |  BibTeX |  DOI | Paper | Slides

This paper presents a novel technique for combining 2D and 2.5D treemaps using multi-perspective views to leverage the advantages of both treemap types. It enables a new form of overview+detail visualization for tree-structured data and contributes new concepts for real-time rendering of and interaction with treemaps. The technique operates by tilting the graphical elements representing inner nodes using affine transformations and animated state transitions. We explain how to mix orthogonal and perspective projections within a single treemap. Finally, we show application examples that benefit from the reduced interaction overhead.

@inproceedings{limberger2017-mixed, 
 author = {Limberger, Daniel and Scheibel, Willy and Trapp, Matthias and D{\"o}llner, J{\"u}rgen}, 
 booktitle = {2017 21st International Conference Information Visualisation (IV)}, 
 title = {Mixed-Projection Treemaps: A Novel Approach Mixing 2D and 2.5D Treemaps}, 
 year = {2017}, 
 location = {London, UK},
 pages = {164-169}, 
 doi = {10.1109/iV.2017.67}, 
 ISSN = {2375-0138}, 
 keywords = {computer animation; data visualisation; rendering (computer graphics); tree data structures;multiperspective views;treemap types;overview+detail visualization;perspective projections;single treemap;2D treemaps;2.5D treemaps;mixed-projection treemaps;tree-structured data;graphical elements;animated state transitions;reduced interaction overhead;Two dimensional displays;Rendering (computer graphics);Visualization;Data visualization;Three-dimensional displays;Layout;Navigation;Information Visualization;Overview+Detail;Treemaps;2.5D Treemaps;Multi-perspective Views},
}
Thumbnail of Progressive High-Quality Rendering for Interactive Information Cartography using WebGL

Progressive High-Quality Rendering for Interactive Information Cartography using WebGL

Daniel Limberger, Marcel Pursche, Jan Klimke, and Jürgen Döllner
Proceedings of the International Conference on 3D Web Technology 2017, Best Paper Award

Abstract |  BibTeX |  DOI | Paper

Information cartography services provided via web-based clients using real-time rendering do not always necessitate a continuous stream of updates in the visual display. This paper shows how progressive rendering by means of multi-frame sampling and frame accumulation can introduce high-quality visual effects using robust and straightforward implementations. For it, (1) a suitable rendering loop is described, (2) WebGL limitations are discussed, and (3) an adaption of THREE.js featuring progressive anti-aliasing, screen-space ambient occlusion, and depth of field is detailed. Furthermore, sampling strategies are discussed and rendering performance is evaluated, emphasizing the low per-frame costs of this approach.

@inproceedings{limberger2017-progressive,
 author = {Limberger, Daniel and Pursche, Marcel and Klimke, Jan and D\"{o}llner, J\"{u}rgen},
 title = {Progressive High-quality Rendering for Interactive Information Cartography Using WebGL},
 booktitle = {Proceedings of the 22Nd International Conference on 3D Web Technology},
 series = {Web3D '17},
 year = {2017},
 isbn = {978-1-4503-4955-0},
 location = {Brisbane, Queensland, Australia},
 pages = {8:1--8:4},
 articleno = {8},
 numpages = {4},
 url = {http://doi.acm.org/10.1145/3055624.3075951},
 doi = {10.1145/3055624.3075951},
 acmid = {3075951},
 publisher = {ACM},
 address = {New York, NY, USA},
 keywords = {WebGL, interactive visualization, mobile, progressive rendering},
} 
Thumbnail of Reducing Visual Complexity in Software Maps using Importance-based Aggregation of Nodes

Reducing Visual Complexity in Software Maps using Importance-based Aggregation of Nodes

Daniel Limberger, Willy Scheibel, Sebastian Hahn, and Jürgen Döllner
Proceedings of the International Conference on Information Visualization Theory and Applications 2017

Abstract |  BibTeX |  DOI | Paper | Slides

Depicting massive software system data using treemaps can result in visual clutter and increased cognitive load. This paper introduces an adaptive level-of-detail (LoD) technique that uses scoring for interactive aggregation on a per-node basis. The scoring approximates importance by degree-of-interest measures as well as screen and user-interaction scores. The technique adheres to established aggregation guidelines and was evaluated by means of two user studies. The first investigates task completion time in visual search. The second evaluates the readability of the presented nesting level contouring for aggregates. With the adaptive LoD technique software maps allow for multi-resolution depictions of software system information while facilitating annotation and efficient identification of important nodes.

@inproceedings{limberger2017-aggregation,
  author = {Limberger, Daniel and Scheibel, Willy and Hahn, Sebastian and D{\"o}llner, J{\"u}rgen},
  title = {Reducing Visual Complexity in Software Maps using Importance-based Aggregation of Nodes},
  booktitle = {Proceedings of the 12th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications - Volume 3: IVAPP, (VISIGRAPP 2017)},
  year = {2017},
  pages = {176-185},
  doi = {10.5220/0006267501760185},
  isbn = {978-989-758-228-8},
}
Thumbnail of Dynamic 2.5D Treemaps using Declarative 3D on the Web

Dynamic 2.5D Treemaps using Declarative 3D on the Web

Daniel Limberger, Willy Scheibel, Stefan Lemme, and Jürgen Döllner
Proceedings of the International Conference on 3D Web Technology 2016

Abstract |  BibTeX |  DOI | Paper | Slides | Source Code | Demo

The 2.5D treemap represents a general purpose visualization technique to map multi-variate hierarchical data in a scalable, interactive, and consistent way used in a number of application fields. In this paper, we explore the capabilities of Declarative 3D for the web-based implementation of 2.5D treemap clients. Particularly, we investigate how X3DOM and XML3D can be used to implement clients with equivalent features that interactively display 2.5D treemaps with dynamic mapping of attributes. We also show a first step towards a glTF-based implementation. These approaches are benchmarked focusing on their interaction capabilities with respect to rendering and speed of dynamic data mapping. We discuss the results for our representative example of a complex 3D interactive visualization technique and summerize recommendations for improvements towards operational web clients.

@inproceedings{limberger2016-declarative-treemaps,
  author = {Limberger, Daniel and Scheibel, Willy and Lemme, Stefan and D\"{o}llner, J\"{u}rgen},
 title = {Dynamic 2.5D Treemaps Using Declarative 3D on the Web},
 booktitle = {Proceedings of the 21st International Conference on Web3D Technology},
 series = {Web3D '16},
 year = {2016},
 isbn = {978-1-4503-4428-9},
 location = {Anaheim, California},
 pages = {33--36},
 numpages = {4},
 doi = {10.1145/2945292.2945313},
 acmid = {2945313},
 publisher = {ACM},
 address = {New York, NY, USA},
 keywords = {2.5D treemap, Dec3D, X3DOM, XML3D, glTF},
}
Thumbnail of Real-time Rendering of High-quality Effects using Multi-frame Sampling

Real-time Rendering of High-quality Effects using Multi-frame Sampling

Daniel Limberger and Jürgen Döllner
ACM SIGGRAPH Posters 2016

Abstract |  BibTeX |  Poster | Source Code | Demo

In a rendering environment of comparatively sparse interaction, e.g., digital production tools, image synthesis and its quality do not have to be constrained to single frames. This work analyzes strategies for highly economically rendering of state-of-the-art rendering effects using progressive multi-frame sampling in real-time. By distributing and accumulating samples of sampling-based rendering techniques (e.g., anti-aliasing, orderindependent transparency, depth-of-field and shadowing, ambient occlusion, screen-space reflections) over multiple frames, images of very high quality can be synthesized with unequaled resource-efficiency.

@inproceedings{limberger2016-multi-frame-sampling,
 author = {Limberger, Daniel and D\"{o}llner, J\"{u}rgen},
 title = {Real-time Rendering of High-quality Effects Using Multi-frame Sampling},
 booktitle = {ACM SIGGRAPH 2016 Posters},
 series = {SIGGRAPH '16},
 year = {2016},
 isbn = {978-1-4503-4371-8},
 location = {Anaheim, California},
 pages = {79:1--79:1},
 articleno = {79},
 numpages = {1},
 doi = {10.1145/2945078.2945157},
 acmid = {2945157},
 publisher = {ACM},
 address = {New York, NY, USA},
 keywords = {accumulation, progressive rendering, sampling},
}
Thumbnail of Evaluation of Sketchiness as a Visual Variable for 2.5D Treemaps

Evaluation of Sketchiness as a Visual Variable for 2.5D Treemaps

Daniel Limberger, Carolin Fiedler, Sebastian Hahn, Matthias Trapp, and Jürgen Döllner
Proceedings of the International Conference on Information Visualization 2016

Abstract |  BibTeX |  DOI | Paper

Treemaps serve as generic, effective tools to display, explore, and analyze multi-variate tree data in a scalable, interactive, and consistent way In this paper, we discuss and evaluate sketchiness as visual variable of 2.5D treemaps. Sketchy rendering techniques allow us to map data, e.g., about uncertainty, imprecision, or vagueness, independently from mappings to other visual variables such as size, color, and height. To this end, we present a design space for sketchy rendering for 2.5D treemaps and corresponding implementation of a real-time sketchy rendering technique. The results of three user studies carried out indicate that sketchiness is a promising candidate for an independent visual variable for 2.5D treemaps, in particular to map ordinal data with a small range such as data that qualifies map items, it shows no strong interference with other visual variables such as color and height due to the regular gestalt of blocks and, hence, allows us to extend the expressiveness of 2.5D treemaps.

@inproceedings{limberger2016-sketchiness-treemaps, 
 author = {Limberger, Daniel and Fiedler, Carolin and Hahn, Sebastian and Trapp, Matthias and D{\"{o}}llner, J{\"{u}}rgen}, 
 title = {Evaluation of Sketchiness as a Visual Variable for 2.5D Treemaps}, 
 booktitle = {Proceedings of the International Conference on Information Visualisation (IV)}, 
 year = {2016}, 
 pages = {183-189}, 
 doi = {10.1109/IV.2016.61}, 
 month = {July},
 organization = {IEEE},
}
Thumbnail of Progressive Rendering using Multi-frame Sampling

Progressive Rendering using Multi-frame Sampling

Daniel Limberger, Karsten Tausche, Johannes Linke, and Jürgen Döllner
GPU Pro 7: Advanced Rendering Techniques 2016

Abstract |  BibTeX

This chapter presents an approach that distributes sampling over multiple, consecutive frames, and, thereby, enables sampling-based, real-time rendering techniques to be implemented for most graphics hardware and systems in a less complex, straightforward way. This systematic, extensible schema allows developers to effectively handle the increasing implementation complexity of advanced, sophisticated, real-time rendering techniques, while improving responsiveness and reducing required hardware resources.

@article{limberger2016-multi-frame-sampling-pro,
 title = {Progressive Rendering Using Multi-frame Sampling},
 author = {Limberger, Daniel and Tausche, Karsten and Linke, Johannes and D{\"o}llner, J{\"u}rgen},
 journal = {GPU Pro 7: Advanced Rendering Techniques},
 pages = {155},
 year = {2016},
 publisher = {CRC Press}
}

Image Stylization by Interactive Oil Paint Filtering

Amir Semmo, Daniel Limberger, Jan Eric Kyprianidis, and Jürgen Döllner
Computers & Graphics 2016, CGF Cover Contest 2016 (Runner-up)

Abstract |  BibTeX |  DOI | Paper

An interactive system for transforming images into an oil paint look is presented. First, dominant colors from an input image are derived for feature-aware recolorization and quantization to conform with a global color palette. Afterwards, it employs non-linear filtering based on the smoothed structure adapted to the main feature contours of the quantized image to synthesize a paint texture in real-time. Furthermore, a generalized brush-based painting interface is introduced that operates within parameter spaces to locally adjust the level of abstraction of the filtering effects.

@article{semmo2016-oilpaint-stylization,
 author = {Semmo, Amir and Limberger, Daniel and Kyprianidis, Jan Eric and D\"{o}llner, J\"{u}rgen},
 title = {Image Stylization by Interactive Oil Paint Filtering},
 journal = {Computers \& Graphics},
 year = {2016},
 doi = {10.1016/j.cag.2015.12.001}
}

Natural Phenomena as Metaphors for Visualization of Trend Data in Interactive Software Maps

Hannes Würfel, Matthias Trapp, Daniel Limberger, and Jürgen Döllner
Proceedings of the International Symposium on Computer Graphics and Visual Computing 2015

Abstract |  BibTeX |  DOI | Paper

This work explores the suitability of rendering natural phenomena in Software maps for effective communication of changes as well as trends. Therefore, Unreal Engine 4 is prototypically used to render Software maps and natural phenomena, such as fire, clouds, smoke, rain, rust, or shininess in real-time. Trend data is automatically computed by hierarchically accumulating as well as analyzing the underlying software metrics, and is mapped to the additional visual variables.

@inproceedings {wuerfel2015-natural-metaphors,
 author = {W\"{u}rfel, Hannes and Trapp, Matthias and Limberger, Daniel and D\"{o}llner, J\"{u}rgen},
 title = {Natural Phenomena as Metaphors for Visualization of Trend Data in Interactive Software Maps},
 booktitle = {Computer Graphics and Visual Computing (CGVC)},
 editor = {Rita Borgo and Cagatay Turkay},
 year = {2015},
 publisher = {The Eurographics Association},
 isbn = {978-3-905674-94-1},
 doi = {10.2312/cgvc.20151246}
}
Thumbnail of Image Stylization by Oil Paint Filtering Using Color Palettes

Image Stylization by Oil Paint Filtering Using Color Palettes

Amir Semmo, Daniel Limberger, Jan Eric Kyprianidis, and Jürgen Döllner
Proceedings of the International Symposium on Computational Aesthetics 2015, Best Paper Award

Abstract |  BibTeX |  DOI | Paper | Video

This paper presents an approach for transforming images into an oil paint look. A color quantization scheme is proposed that performs feature-aware recolorization using the dominant colors of the input image. In addition, an approach for real-time computation of paint textures is presented that builds on the smoothed structure adapted to the main feature contours of the quantized image. The stylization technique leads to homogeneous outputs in the color domain and enables creative control over the visual output, such as color adjustments and per-pixel parametrizations by means of interactive painting.

@inproceedings{semmo2015-oilpaint-stylization,
 author = {Semmo, Amir and Limberger, Daniel and Kyprianidis, Jan Eric and D\"{o}llner, J\"{u}rgen},
 title = {Image Stylization by Oil Paint Filtering Using Color Palettes},
 booktitle = {Proceedings of the Workshop on Computational Aesthetics},
 series = {CAE '15},
 year = {2015},
 location = {Istanbul, Turkey},
 pages = {149--158},
 numpages = {10},
 doi = {10.2312/exp.20151188},
 acmid = {2811248},
 publisher = {Eurographics Association},
 address = {Aire-la-Ville, Switzerland, Switzerland},
} 

Painting Per-Pixel Parametrization for Interactive Image Filtering

Daniel Limberger and Jürgen Döllner
Expressive Posters 2014

Abstract |  BibTeX |  Poster

This work presents a photo-editing method that enables per-pixel parameter manipulation of image filtering by means of interactive painting. Predefined or custom image filters are exposed to the user, as a parametrizable composition of image operations. Brushes, as sequences of actions mapping user inputs (in terms of brush shape, flow, pressure, etc.) to arbitrary functions or convolution operators, are used to draw within the parameter space. It demonstrates how interactive painting can be used to, e.g., locally tweak parametrization and, furthermore, provides a blueprint for an collaborative photo-editing platform.

@misc{limberger2014-parameter-painting,
 author = {Limberger, Daniel and D{\"o}llner, J{\"u}rgen},
 title = {Painting Per-Pixel Parametrization for Interactive Image Filtering},
 year = {2014},
 month = {8},
 day = {8},
 note = {Poster presented at the Expressive 2014 Poster Session, August 8, Fletcher Challenge Theatre, Harbour Centre},
}

Interactive Software Maps for Web-Based Source Code Analysis

Daniel Limberger, Benjamin Wasty, Jonas Trümper, and Jürgen Döllner
Proceedings of the International Conference on 3D Web Technology 2013

Abstract |  BibTeX |  DOI | Paper | Slides | Video

Software maps—linking 2.5D treemaps, software system structure, and performance indicators—are commonly used to support informed decision making in software-engineering processes. In this paper a web-based rendering system for software maps that achieves both fast client-side page load time and interactive frame rates even with large software maps is presented. The page load time is significantly reduced by efficiently encoding hierarchy and geometry data for the net transport.

@inproceedings{limberger2013-web-based-swmaps,
 author = {Limberger, Daniel and Wasty, Benjamin and Tr\"{u}mper, Jonas and D\"{o}llner, J\"{u}rgen},
 title = {Interactive Software Maps for Web-based Source Code Analysis},
 booktitle = {Proceedings of the 18th International Conference on 3D Web Technology},
 series = {Web3D '13},
 year = {2013},
 isbn = {978-1-4503-2133-4},
 location = {San Sebastian, Spain},
 pages = {91--98},
 numpages = {8},
 doi = {10.1145/2466533.2466550},
 acmid = {2466550},
 publisher = {ACM},
 address = {New York, NY, USA},
 keywords = {3D-treemaps, WebGL, computer aided analysis, decision making, software visualization, web integration},
}

Single-Pass Rendering of Day and Night Sky Phenomena

Daniel Müller (now Limberger), Juri Engel, and Jürgen Döllner
Proceedings of the International Workshop on Vision, Modeling, and Visualization 2012

Abstract |  BibTeX |  DOI | Paper | Slides | Video | Source Code

This paper presents techniques for astronomical based, real-time rendering of skies as seen from low altitudes on earth, in respect to location, date, and time. The techniques allow for composing an atmosphere with sun, multiple cloud layers, moon, bright stars, and Milky Way, into a holistic sky with unprecedented level of detail and diversity. GPU generated, viewpoint-aligned billboards are used to render stars with approximated color, brightness, and scintillations. A similar approach is used to synthesize the moon considering lunar phase, earthshine, shading, and lunar eclipses.

@inproceedings{limberger2012-sky-phenomena,
 author = {Limberger, Daniel and Engel, Juri and D{\"{o}}llner, J{\"{u}}rgen},
 title = {Single-Pass Rendering of Day and Night Sky Phenomena},
 booktitle = {Proceedings of the Vision, Modeling, and Visualization Workshop 2012},
 affiliation = {Hasso-Plattner-Institut, University of Potsdam, Germany},
 publisher = {Eurographics Association},
 booktitle = {Proceedings of the Vision, Modeling, and Visualization Workshop 2012},
 pages = {55--62},
 year = {2012},
 month = {11},
 doi = {10.2312/PE/VMV/VMV12/055-062},
}

Photorealistisches Rendering atmosphärischer Effekte in geovirtuellen 3D-Umgebungen in Echtzeit

Daniel Müller (now Limberger)
Master's Thesis in IT-Systems Engineering 2012

Abstract |  Master's Thesis [de] | Source Code

The document was written and is available in German language only (sorry).

In this work we present a system for image-synthesis of atmospheric effects in virtual 3d environments. It allows realtime rendering of dynamic, high quality environments for background composition (background scenery) for a variety of applications not only in video-games and simulators (e.g., Flight- or vehicle-simulators), but also for architectural and historical visualizations. To ensure ease of integration, only the background associated phenomena are taken into account. Thereby a texture-based, and a simulation-based approach are presented. The texture-based approach targets the imitation of any environment and uses wellknown, texture-based methods with hardly any creative limitations. They are expandable and ideal for applications where, in resprect to the rendering performance, only low capacities can be allocated. The simulation-based, astrophysical approach, in contrast, is based on astronomical algorithms and astrophysical observations. The new models and methods used within this approach, provide the conceptual focus of this work. Both approaches are optimized for rendering dynamic day-night cycles within a single rendering pass and without subsequent processing. They are integrated in a large representative rendering system (OpenSceneGraph). Detailed performance measurements in different scenarios and quality levels show that the system has little effect on overall rendering-speed.

Computergenerierte Bleistiftzeichnungen von 3D-Stadtmodellen

Daniel Müller (now Limberger)
Bachelor's Thesis in IT-Systems Engineering 2009

Abstract |  Bachelor's Thesis [de]

This work summarizes techniques for 3D-image synthesis of pencil or crayon drawings of virtual 3D-city-models in real-time. The document was written and is available in German language only (sorry).

Diese Arbeit befasst sich mit der Erstellung von Bleistiftzeichnungen dreidimensionaler Modelle in Echtzeit und prüft die Anwendbarkeit auf virtuelle 3D-Stadtmodelle. Bisherige Verfahren gehen kaum auf stilprägende subjektive Einflüsse der Zeichner ein. So werden stilrelevante Maßnahmen wie weiche Schatten und Lichteinflüsse durch Umgebungsverdeckung häufig vernachlässigt. Nach einer kurzen Zusammenfassung bisheriger Ansätze zur Nachahmung von Bleistiftzeichnungen, werden effiziente Implementierung für Konturdarstellung und Krümmungsapproximation zur Schraffur vorgestellt. Da die meisten Berechnungen diskretisiert im Bildraum vorgenommen werden, entstehen beim Rendern komplexer 3D-Stadtmodelle störende, mit der Tiefe zunehmende Artefakte. Zur Abschwächung dieser Störfaktoren werden praktische Lösungen wie stilkonforme Tiefenfokussierung diskutiert.