Welcome



Welcome to the Computer Graphics Group at RWTH Aachen University!

The research and teaching activities at our institute focus on geometry acquisition and processing, on interactive visualization, and on related areas such as computer vision, photo-realistic image synthesis, and ultra high speed multimedia data transmission.

In our projects we are cooperating with various industry companies as well as with academic research groups around the world. Results are published and presented at high-profile conferences and symposia. Additional funding sources, among others, are the Deutsche Forschungsgemeinschaft and the European Union.

Geometry Lab Exhibition

On November 3–5 we will be staging the Geometry Lab: an event where works of art meet scientific exhibits. Located in the Ludwig Forum art gallery, the exhibition displays an entire spectrum from classical geometric phenomena to modern research areas. In addition, workshops will be held for participants to fold paper into fascinating forms, build complex structures with Zometool, or even assemble their very own 3D printer.

Sept. 20, 2017

We will be hosting the International Conference on Geometric Modeling and Processing (GMP) in April 2018.

June 19, 2017

We have a paper on Variance-Minimizing Transport Plans for Inter-surface Mapping at SIGGRAPH 2017.

May 2, 2017

We have a paper on City Reconstruction and Visualization from Public Data Sources at the Eurographics Workshop on Urban Data Modelling and Visualisation 2016.

Nov. 8, 2016

We have a paper on the Geodesic Iso-Curve Signature at the 21st International Symposium on Vision, Modeling and Visualization.

Sept. 9, 2016

We have a paper on interactive quad meshing at SIGGRAPH Asia 2016.

Sept. 6, 2016

Recent Publications

Directional Field Synthesis, Design, and Processing

SIGGRAPH '17 Courses, July 30 - August 03, 2017, Los Angeles, CA, USA

Direction fields and vector fields play an increasingly important role in computer graphics and geometry processing. The synthesis of directional fields on surfaces, or other spatial domains, is a fundamental step in numerous applications, such as mesh generation, deformation, texture mapping, and many more. The wide range of applications resulted in definitions for many types of directional fields: from vector and tensor fields, over line and cross fields, to frame and vector-set fields. Depending on the application at hand, researchers have used various notions of objectives and constraints to synthesize such fields. These notions are defined in terms of fairness, feature alignment, symmetry, or field topology, to mention just a few. To facilitate these objectives, various representations, discretizations, and optimization strategies have been developed. These choices come with varying strengths and weaknesses. This course provides a systematic overview of directional field synthesis for graphics applications, the challenges it poses, and the methods developed in recent years to address these challenges.

 

Variance-Minimizing Transport Plans for Inter-surface Mapping

SIGGRAPH 2017

We introduce an efficient computational method for generating dense and low distortion maps between two arbitrary surfaces of same genus. Instead of relying on semantic correspondences or surface parameterization, we directly optimize a variance-minimizing transport plan between two input surfaces that defines an as-conformal-as-possible inter-surface map satisfying a user-prescribed bound on area distortion. The transport plan is computed via two alternating convex optimizations, and is shown to minimize a generalized Dirichlet energy of both the map and its inverse. Computational efficiency is achieved through a coarse-to-fine approach in diffusion geometry, with Sinkhorn iterations modified to enforce bounded area distortion. The resulting inter-surface mapping algorithm applies to arbitrary shapes robustly, with little to no user interaction.

 

Boundary Element Octahedral Fields in Volumes

ACM Transactions on Graphics

The computation of smooth fields of orthogonal directions within a volume is a critical step in hexahedral mesh generation, used to guide placement of edges and singularities. While this problem shares high-level structure with surface-based frame field problems, critical aspects are lost when extending to volumes, while new structure from the flat Euclidean metric emerges. Taking these considerations into account, this paper presents an algorithm for computing such “octahedral” fields. Unlike existing approaches, our formulation achieves infinite resolution in the interior of the volume via the boundary element method (BEM), continuously assigning frames to points in the interior from only a triangle mesh discretization of the boundary. The end result is an orthogonal direction field that can be sampled anywhere inside the mesh, with smooth variation and singular structure in the interior even with a coarse boundary. We illustrate our computed frames on a number of challenging test geometries. Since the octahedral frame field problem is relatively new, we also contribute a thorough discussion of theoretical and practical challenges unique to this problem.

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