Joint PhD Degree Programme Graz University of Technology and Nanyang Technological University

The Institute for Computer Graphics and Knowledge Visualization participates since 2012 in the joint PhD programme, with a focus on research in Geometric Modeling, Visualization and Novel Applications in Visual Computing. We here describe our ongoing and future work. For more information, please contact the Principal Investigators:

Project Page NTU

For more general inforamtion on the dual degree program, please see here.

Current projects

Domain Specific Procedural Modeling of 3D Shapes

Because modeling via code can often by quite tedious, simplifications for various modeling domains are of great help. One example is shape grammars. They are formal grammars (often context-free) that generate geometry. For regular and hierarchical structures, like building facades, they provide a much easier way of modeling compared to other procedural techniques. Therefore, finding new domain specific ways for describing 3D models or further developing existing ones, will increase the potential of procedural modeling. This project looks at application areas like roof modeling and advanced shape grammars systems.

Researcher: Johannes Edelsbrunner
TU Graz Supervisor: Sven Havemann
NTU Supervisor: Alexei Sourin


  • Edelsbrunner, J., Krispel, U., Havemann, S., Sourin, A., & Fellner, D. W. (2014, October). Constructive Roof Geometry. In Cyberworlds (CW), 2014 International Conference on (pp. 63-70).
  • Zmugg, R., Thaller, W., Krispel, U., Edelsbrunner, J., Havemann, S., & Fellner, D. W. (2014). Procedural architecture using deformation-aware split grammars. The Visual Computer, 30(9), 1009-1019.
  • Zmugg, R., Thaller, W., Krispel, U., Edelsbrunner, J., Havemann, S., & Fellner, D. W. (2013, October). Deformation-aware split grammars for architectural models. In Cyberworlds (CW), 2013 International Conference on (pp. 4-11).

Open Projects

Geometry Processing

The goal of the project is to make it easier to produce good coarse 3D meshes from densely scanned data. We have methods for finding curvatures and features in a point cloud or triangle mesh and, based on those, developed a software tool which aids the manual generation of good subdivision control meshes from scan data. We want to investigate methods to automatically reduce a point cloud or triangle mesh to a good coarse subdivision base mesh. A good subdivision mesh is not only accurate and coarse but also regular. The method for finding high quality quadrilateral representations should be general and applicable to complex meshes of arbitrary topology.

Researcher: open to application
TU Graz Supervisor: Ursula Augsdörfer
NTU Supervisor: Alexei Sourin


  • David Bommes, Bruno Lévy, Nico Pietroni, Enrico Puppo, Claudio Silva, Marco Tarini, Denis Zorin, Quad-Mesh Generation and Processing: A Survey, Computer Graphics Forum 32 (6), 51-76
  • J. Shen, J. Kosinka, M. A. Sabin, N. A. Dodgson, Conversion of trimmed NURBS surfaces to Catmull-Clark subdivision surfaces,  Computer Aided Geometric Design 31 (7-8):486-498
  • U. H. Augsdörfer, N. A. Dodgson, and M. A. Sabin, Artifact analysis on B-splines, box-splines and other surfaces defined by quadrilateral polyhedra, Computer Aided Geometric Design 28 (3):177-197, ISSN 0167-8396
  • T. J. Cashman, U. H. Augsdörfer, N. A. Dodgson, and M. A. Sabin, NURBS with extraordinary points: high-degree non-uniform subdivision surfaces,  ACM Transactions on Graphics 28 (3): Article 46, Proc. SIGGRAPH 2009, ISSN 0730-0301
  • U. H. Augsdörfer, N. A. Dodgson, and M. A. Sabin, Tuning subdivision by minimising gaussian curvature variation near extraordinary vertices, Computer Graphics Forum 25 (3):263-272, (Proc. Eurographics), ISSN 0167-7055

3D Shape Retrieval and Analysis

Due to recent advances in 3D acquisition and modeling, increasingly large amounts of 3D shape data become available in many application domains. Coping with large 3D shape data requires effective and efficient techniques to support 3D searching, exploring, analyzing and processing tasks. Our research group works on feature-based approaches for 3D shape retrieval including sketch- and example-based methods; clustering and classification of shape repositories for annotation and visual exploration; and on similarity-based methods for restoration of fragmented or incomplete shapes. In this project, we want to evaluate novel feature-based shape analysis methods to support one or more of the above mentioned problems. The methods to be researched are informed by new application needs in domains such as Computer Aided Design and Digital Archeology.

Researcher: open to application
TU Graz Supervisor: Tobias Schreck
NTU Supervisor: Alexei Sourin


  • Sipiran, R. Gregor, and T. Schreck. Approximate symmetry detection in partial 3D meshes. Wiley Computer Graphics Forum, 33(7):131-140, 2014.
  • R. Gregor, I. Sipiran, G. Papaioannou, T. Schreck, A. Andreadis, and P. Mavridis. Towards automated 3D reconstruction of defective cultural heritage objects. In Proc. EG Workshop on Graphics and Cultural Heritage, pages 135-144. Eurographics, 2014.
  • B. Li, Y. Lu, A. Godil, T. Schreck, B. Bustos, A. Ferreira, T. Furuya, M. Fonseca, H. Johan, T. Matsuda, R. Ohbuchi, P. Pascoal, and J. Saavedra. A comparison of methods for sketch-based 3D shape retrieval. Elsevier Computer Vision and Image Understanding, 119:57-80, 2014.
  • I. Sipiran, B. Bustos, and T. Schreck. Data-aware 3D partitioning for generic shape retrieval. Computers & Graphics Special Issue on 3D Object Retrieval, 37(5):460-472, 2013.
  • J. Tangelder and R. Veltkamp. A survey of content based 3d shape retrieval methods. Multimedia Tools Appl., 39(3):441-471, 2008.