Publications

Thumbnail of Mixed-projection Treemaps: A novel Perspective on Treemaps
Mixed-projection Treemaps: A novel Perspective on Treemaps

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

Abstract

2D treemaps are a space-filling visualization technique that facilitate exploration of non-spatial, attributed, tree-structured data using the visual variables size and color. In extension thereto, 2.5D treemaps introduce height for additional information display. This extension entails challenges such as increased rendering effort, occlusion, or the need for navigation techniques that counterbalance the advantages of 2D treemaps to a certain degree. 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 complex treemaps and contributes new concepts for real-time rendering of and interaction with mixed-projection treemaps. The technique operates by tilting up inner nodes using affine transformations and animated state transitions. The mixed use of orthogonal and perspective projections is discussed and application examples that facilitate exploration of multi-variate data and benefit from the reduced interaction overhead are demonstrated.

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

Abstract

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.

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

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.

@conference{lshd2017-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, 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{lsld2016-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{ld2016-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{lfhtd2016-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{ltld2016-multi-frame-sampling,
 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{slkd2016-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 {wtld2015-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{slkd2015-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{ld2014-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{lwtd2013-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 (Limberger), Juri Engel, and Jürgen Döllner
Proceedings of the International Workshop on Vision, Modeling, and Visualization 2012

Abstract, BibTeX, DOI, Paper, Slides, Video, Google 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{led2012-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},
}

Projects

glbinding

I initiated, (co-)designed, and continue to maintain this state-of-the-art, cross-platform C++ binding for the OpenGL API.

Project 

Thumbnail of globjects
globjects

A cross-platform C++ interface for OpenGL's programmable pipeline that I (co-)designed and continue to support.

Project 

Tangible Treemaps

We experimented with 3d printed, colored, and labeled 2.5D treemaps by means of feasibility and interaction.

 

Thumbnail of Publicity & Web Chair
Publicity & Web Chair

Disseminatied conference information and redesigned the Logo and Website of the IEEE Conf. on Software Visualization.

Conference Website 

Thumbnail of Game Programming
Game Programming

While enjoying co-lecturing multiple Game Programming Seminars, I like editing videos to promote these rare seminars.

Video 

Path Tracing Test

Basic test for progressive path tracing of triangle-based meshes, running on the GPU using OpenGL.

Project 

Thumbnail of Miniature Baby Print
Miniature Baby Print

In 2011 I created my first miniature 3D print of my two month old daughter as a present for her grand parents.

Video 

Thumbnail of OSG Himmel
OSG Himmel

OSG library featuring dynamic, immersive, textured or date-time and location based, procedural skies.

Project 

Talks

07/23/16
Dynamic 2.5D Treemaps using Declarative 3D on the Web

ACM SIGGRAPH Web3D Conference 2016, Anaheim, CA, USA | Slides

05/07/15
Monitoring Software Quality Aspects using Software Maps

SAPPHIRE NOW 2015, Orlando, FL, USA

11/20/13
Rendering of Day and Night Sky Phenomena in Interactive 3D Geovirtual Environments

DGKF & DGPF Workshop "3D-Stadmodelle", Bonn, Germany | Slides

06/20/13
Annotating 3D Content in Interactive, Virtual Worlds

Web3D2013, San Sebastian, Spain

06/20/13
Interactive Software Maps for Web-Based Source Code Analysis

Web3D2013, San Sebastian, Spain | Slides

11/12/12
Single-Pass Rendering of Day and Night Sky Phenomena

VMV2012, Magdeburg, Germany | Slides

06/08/10
Semantic-Based, Non-Photorealisitc Visualization of 3D Geovirtual Environments

58. Deutscher Kartographentag, Berlin, Germany

Teaching

2017 : Summer Term
2016/17 : Winter Term

Advanced Programming in C++
Lecture (MA), Tutor & Co-Lecturer

Methods and Techniques of Information Visualization
Seminar (MA), Tutor

Real-time Monitoring of Massive File Systems
Project (MA), Supervisor

2016 : Summer Term

Computergraphics II
Lecture (BA), Tutor & Co-Lecturer

Methods and Techniques of Software Visualization
Seminar (MA), Tutor

Introduction to Visual Analytics
Seminar (BA), Tutor

Massive Information Mining for Software Analytics
Project (BA), Supervisor

2015/16 : Winter Term

Systems Engineering for Software Analytics
Seminar (MA), Tutor

2015 : Summer Term

Automated Visual Software Analytics
Lecture (massive open online course), Tutor

Visualization of System Evolution
Seminar (MA), Tutor

Programming Technique II
Lecture (BA), Tutor & Co-Lecturer

Software Analysis and Visualization
Project (BA), Supervisor

2014/15 : Winter Term

Visualization for Interactive Software Analytics
Seminar (MA), Tutor

Introduction to Programming C++
Lecture (MA Geo), Lecturer

Game Programming
Lecture/Seminar (BA), Tutor & Co-Lecturer

Introduction to 3D Computergraphics
Youth Academy, Lecturer

2014 : Summer Term

Information Visualization
Seminar (MA), Tutor

Graphics Programming with OpenGL and C++
Lecture/Seminar (BA), Tutor & Lecturer

Software Analysis and Visualization
Project (BA), Supervisor

2013/14 : Winter Term

Software Analytics
Seminar (MA), Tutor

Game Programming
Lecture/Seminar (BA), Tutor & Co-Lecturer

Computergraphics II
Lecture (BA), Tutor & Co-Lecturer

Introduction to 3D Computergraphics
Youth Academy, Lecturer

2013 : Summer Term

Software Visualization Techniques
Seminar (MA), Tutor

Graphics Programming with OpenGL and C++
Lecture/Seminar (BA), Tutor & Lecturer

Computergraphics I
Lecture (BA), Tutor & Co-Lecturer

2012/13 : Winter Term

Concepts and Techniques for 3D Visualization
Seminar (MA), Tutor

Game Programming
Lecture/Seminar (BA), Tutor & Co-Lecturer

Computergraphics II
Lecture (BA), Tutor & Co-Lecturer

Introduction to 3D Computergraphics
Youth Academy, Lecturer

Contact

cgdaniel@outlook.com

Other: daniel.limberger@hpi.de, limberger@cginternals.com

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