Welcome



Welcome to the Computer Graphics Group at University of Bern!

For the previous Computer Graphics Group website led by Professor Zwicker click here.

The research and teaching activities at our institute

Results are published

Invited Talks from Hextreme team UCL, Belgium

Pierre-Alexandre Beaufort and Maxence Reberol (both from the hextreme team at UC Louvain) will be visiting us. There will be two talks on Wednesday 4th, 11:00 and 14:00 respectively, see Talks section to learn more.

March 4, 2020

Invited talk, Max Lyon. RWTH Aachen University

Title: Parametrization Quantization with Free Boundaries for Trimmed Quad Meshing Friday, Feb. 21st Time: 10:00 Location: N10, room 302

Feb. 18, 2020

Invited talk Valentin Nigolian

Valentin Nigolian visited our group and gave a talk about his research project titled: INVANER: INteractive VAscular Network Editing and Repair

Oct. 1, 2019

AlgoHex: ERC starting grant

Prof. Bommes was awarded an ERC starting grant for project AlgoHex: Algorithmic Hexahedral Mesh Generation. Here the link to the official announcement on the University of Bern website (German) (English)

Sept. 4, 2019

Selective Padding for Polycube-based Hexahedral Meshing

The paper "Selective Padding for Polycube-based Hexahedral Meshing" was accepted to Computer Graphics Forum.

Dec. 21, 2018

SIGGRAPH 2019 technical committee

David Bommes will serve on the technical papers committee for SIGGRAPH2019, which will take place in Los Angeles, USA. SIGGRAPH is the premiere international conference for computer graphics and interactive techniques.

Nov. 1, 2018

Recent Publications

Octahedral Frames for Feature-Aligned Cross Fields

ACM Transactions on Graphics

We present a method for designing smooth cross fields on surfaces that automatically align to sharp features of an underlying geometry. Our approach introduces a novel class of energies based on a representation of cross fields in the spherical harmonic basis. We provide theoretical analysis of these energies in the smooth setting, showing that they penalize deviations from surface creases while otherwise promoting intrinsically smooth fields. We demonstrate the applicability of our method to quad meshing and include an extensive benchmark comparing our fields to other automatic approaches for generating feature-aligned cross fields on triangle meshes.

 

Algebraic Representations for Volumetric Frame Fields

ACM Transactions on graphics

Field-guided parameterization methods have proven effective for quad meshing of surfaces; these methods compute smooth cross fields to guide the meshing process and then integrate the fields to construct a discrete mesh. A key challenge in extending these methods to three dimensions, however, is representation of field values. Whereas cross fields can be represented by tangent vector fields that form a linear space, the 3D analog—an octahedral frame field—takes values in a nonlinear manifold. In this work, we describe the space of octahedral frames in the language of differential and algebraic geometry. With this understanding, we develop geometry-aware tools for optimization of octahedral fields, namely geodesic stepping and exact projection via semidefinite relaxation. Our algebraic approach not only provides an elegant and mathematically sound description of the space of octahedral frames but also suggests a generalization to frames whose three axes scale independently, better capturing the singular behavior we expect to see in volumetric frame fields. These new odeco frames, so called as they are represented by orthogonally decomposable tensors, also admit a semidefinite program–based projection operator. Our description of the spaces of octahedral and odeco frames suggests computing frame fields via manifold-based optimization algorithms; we show that these algorithms efficiently produce high-quality fields while maintaining stability and smoothness.

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