Pierre Alliez

pierre-alliezPierre Alliez
Inria Research Director, Head of science, Team leader
Project-team TITANE
Inria Sophia Antipolis – Méditerranée

Contact information
Pierre Alliez
Inria Sophia-Antipolis
2004 route des Lucioles BP 93
06902 Sophia-Antipolis cedex
Office: Y313 (Byron building)
Phone: (33) 4 92 38 76 77
Fax: (33) 4 97 15 53 95
Email: pierre.alliez (at) inria.fr

My main research interests are on topics commonly referred to as Geometry Processing: geometry compression, surface approximation, mesh parameterization, surface remeshing, mesh generation and surface reconstruction. Initially considered as a subfield of Computer Graphics and Computational Geometry, Geometry Processing has developed over the last years into a whole research community seeking automatic, computerized processing of complex shapes. My overall research goal is to design methods which are both theoretically founded and computationally tractable to render them robust to unprocessed inputs, reliable, and, above all, with real impact on technological applications. Targeting these properties requires a complete rethinking of the geometry pipeline and of its foundational algorithms so that bottlenecks (i.e., parts of the pipeline which are too labor–intensive or too brittle for practitioners) are removed.

I received the Eurographics Young Researcher Award 2005. I was program co-chair of the EUROGRAPHICS Symposium on Geometry Processing 2008, Pacific Graphics 2010, Geometric Modeling and Processing 2014, EUROGRAPHICS 2019 and Solid and Physical Modeling 2019.
I was an associate editor of the ACM Transactions on Graphics between 2010 and 2017, of Graphical Models since 2010, and of Computer Aided Geometric Design since 2014. I have been awarded in 2011 a Starting Grant from the ERC (European Research Council), entitled “IRON”, which stands for “Robust Geometry Processing”. I have been awarded in 2017 an ERC proof of concept grant, entitled “TITANIUM” (software components for robust geometry processing).

Complete list
See google scholar
– See list of publications on HAL
– Publications on TITANE web site

Recent publications:

Cost-driven framework for progressive compression of textured meshes. Cédric Portaneri, Pierre Alliez, Michael Hemmer, Lukas Birklein, Elmar Schoemer. 10th ACM Multimedia Systems Conference, 2019. Best paper award.

Abstract: Recent advances in digitization of geometry and radiometry generate in routine massive amounts of surface meshes with texture or color attributes. This large amount of data can be compressed using a progressive approach which provides at decoding low complexity levels of details (LoDs) that are continuously refined until retrieving the original model. The goal of such a progressive mesh compression algorithm is to improve the overall quality of the transmission for the user, by optimizing the rate-distortion trade-off. In this paper, we introduce a novel meaningful measure for the cost of a progressive transmission of a textured mesh by observing that the rate-distortion curve is in fact a staircase, which enables an effective comparison and optimization of progressive transmissions in the first place. We contribute a novel generic framework which utilizes the cost function to encode triangle surface meshes via multiplexing several geometry reduction steps (mesh decimation via half-edge or full-edge collapse operators, xyz quantization reduction and uv quantization reduction). This framework can also deal with textures by multiplexing an additional texture reduction step. We also design a texture atlas that enables us to preserve texture seams during decimation while not impairing the quality of resulting LODs. For encoding the inverse mesh decimation steps we further contribute a significant improvement over the state-of-the-art in terms of rate-distortion performance and yields a compression-rate of 22:1, on average. Finally, we propose a unique single-rate alternative solution using a selection scheme of a subset among LODs, optimized for our cost function, and provided with our atlas that enables interleaved progressive texture refinements.

Selective Padding for Polycube-Based Hexahedral Meshing. G. Cherchi, Pierre Alliez, R. Scateni, M. Lyon, D. Bommes.  Computer Graphics Forum, Wiley, 2019.

Abstract : Hexahedral meshes generated from polycube mapping often exhibit a low number of singularities but also poor quality elements located near the surface. It is thus necessary to improve the overall mesh quality, in terms of the minimum Scaled Jacobian (MSJ) or average Scaled Jacobian (ASJ). Improving the quality may be obtained via global padding (or pillowing), which pushes the singularities inside by adding an extra layer of hexahedra on the entire domain boundary. Such a global padding operation suffers from a large increase of complexity, with unnecessary hexahedra added. In addition, the quality of elements near the boundary may decrease. We propose a novel optimization method which inserts sheets of hexahedra so as to perform selective padding, where it is most needed for improving the mesh quality. A sheet can pad part of the domain boundary, traverse the domain and form singularities. Our global formulation, based on solving a binary problem, enables us to control the balance between quality improvement, increase of complexity and number of singularities. We show in a series of experiments that our approach increases the MSJ value and preserves (or even improves) the ASJ, while adding fewer hexahedra than global padding.

Curved Optimal Delaunay Triangulation
Leman Feng, Pierre Alliez, Laurent Busé, Hervé Delingette, and Mathieu Desbrun.ACM Transactions on Graphics (SIGGRAPH), 37(4), Art. 61, 2018.
Abstract: Meshes with curvilinear elements hold the appealing promise of enhanced geometric flexibility and higher-order numerical accuracy compared to their commonly-used straight-edge counterparts. However, the generation of curved meshes remains a computationally expensive endeavor with current meshing approaches: high-order parametric elements are notoriously difficult to conform to a given boundary geometry, and enforcing a smooth and non-degenerate Jacobian everywhere brings additional numerical difficulties to the meshing of complex domains. In this paper, we propose an extension of Optimal Delaunay Triangulations (ODT) to curved and graded isotropic meshes. By exploiting a continuum mechanics interpretation of ODT instead of the usual approximation theoretical foundations, we formulate a very robust geometry and topology optimization of Bézier meshes based on a new simple functional promoting isotropic and uniform Jacobians throughout the domain. We demonstrate that our resulting curved meshes can adapt to complex domains with high precision even for a small count of elements thanks to the added flexibility afforded by more control points and higher order basis functions.
Variance-Minimizing Transport Plans for Inter-surface Mapping

Manish Mandad, David Cohen-Steiner, Leif Kobbelt, Pierre Alliez and Mathieu Desbrun.

ACM Transactions on Graphics (SIGGRAPH), 2017.

See also Supplemental Material.

Abstract: 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.

 ovt Optimal Voronoi Tessellations with Hessian-based Anisotropy
Max Budninskiy, Beibei Liu, Fernando de Goes, Yiying Tong, Pierre Alliez, and Mathieu Desbrun.
ACM Transactions on Graphics (SIGGRAPH Asia), 36(6), 2016. Supplemental Material.
Abstract: This paper presents a variational method to generate cell complexes with local anisotropy conforming to the Hessian of any given convex function and for any given local mesh density. Our formulation builds upon approximation theory to offer an anisotropic extension of Centroidal Voronoi Tessellations which can be seen as a dual form of Optimal Delaunay Triangulation. We thus refer to the resulting anisotropic polytopal meshes as Optimal Voronoi Tessellations. Our approach sharply contrasts with previous anisotropic versions of Voronoi diagrams as it employs first-type Bregman diagrams, a generalization of power diagrams where sites are augmented with not only a scalar-valued weight but also a vectorvalued shift. As such, our OVT meshes contain only convex cells with straight edges, and admit an embedded dual triangulation that is combinatorially-regular. We show the effectiveness of our technique using off-the-shelf computational geometry libraries.
LieSymmetry Symmetry and Orbit Detection via Lie-Algebra Voting.
Zeyun Shi, Pierre Alliez, Mathieu Desbrun, Hujun Bao, and Jin Huang.
EUROGRAPHICS Symposium of Geometry Processing, 2016. (Best paper award)
See also supplemental material.
Abstract: In this paper, we formulate an automatic approach to the detection of partial, local, and global symmetries and orbits in arbitrary 3D datasets. We improve upon existing voting-based symmetry detection techniques by leveraging the Lie group structure of geometric transformations. In particular, we introduce a logarithmic mapping that ensures that orbits are mapped to linear subspaces, hence unifying and extending many existing mappings in a single Lie-algebra voting formulation. Compared to previous work, our resulting method offers significantly improved robustness as it guarantees that our symmetry detection of an input model is frame, scale, and reflection invariant. As a consequence, we demonstrate that our approach efficiently and reliably discovers symmetries and orbits of geometric datasets without requiring heavy parameter tuning.
survey-rec A Survey of Surface Reconstruction from Point Clouds
Matthew Berger, Andrea Tagliasacchi, Lee M. Seversky, Pierre Alliez, Gael Guennebaud, Joshua A. Levine, Andrei Sharf and Claudio Silva.
Computer Graphics Forum, 2016. Extended version of a EUROGRAPHICS state of the art report.
The area of surface reconstruction has seen substantial progress in the past two decades. The traditional problem addressed by surface reconstruction is to recover the digital representation of a physical shape that has been scanned, where the scanned data contains a wide variety of defects. While much of the earlier work has been focused on reconstructing a piece-wise smooth representation of the original shape, recent work has taken on more specialized priors to address significantly challenging data imperfections, where the reconstruction can take on different representations – not necessarily the explicit geometry. We survey the field of surface reconstruction, and provide a categorization with respect to priors, data imperfections, and reconstruction output. By considering a holistic view of surface reconstruction, we show a detailed characterization of the field, highlight similarities between diverse reconstruction techniques, and provide directions for future work in surface reconstruction.
tolerance-volume Isotopic Approximation within a Tolerance Volume
Manish Mandad, David Cohen-Steiner, Pierre Alliez
ACM Transactions on Graphics, 2015.
Proceedings of ACM SIGGRAPH 2015
Download slides
LOD Generation for Urban Scenes
Yannick Verdie, Florent Lafarge, Pierre Alliez.
ACM Transactions on Graphics, 2015.
Presented at ACM SIGGRAPH 2015
Structure-Aware Mesh Decimation
David Salinas, Florent Lafarge and Pierre Alliez
Computer Graphics Forum, 2015 (to appear)
Indoor Scene Reconstruction using Feature Sensitive Primitive Extraction and Graph-cut.
Sven Oesau, Florent Lafarge and Pierre Alliez
ISPRS Journal of Photogrammetry and Remote Sensing, Vol. 90: pages 68-82, 2014
Zometool Shape Approximation
Henrik Zimmer, Florent Lafarge, Pierre Alliez and Leif Kobbelt.
Proceedings of Geometric Modeling and Processing 2014.
State of the Art in Surface Reconstruction from Point Clouds.
Matthew Berger, Andrea Tagliasacchi, Lee Seversky, Pierre Alliez, Joshua Levine, Andrei Sharf, Claudio Silva.
EUROGRAPHICS State of the Art report, 2014.
CGALmesh: a Generic Framework for Delaunay Mesh Generation.
Clément Jamin, Pierre Alliez, Mariette Yvinec, Jean-Daniel Boissonnat.
ACM Transactions on Mathematical Software, Association for Computing Machinery (ACM), 2014.
sig13 Integer-Grid Maps for Reliable Quad Meshing
David Bommes, Marcel Campen, Hans-Christian Ebke, Pierre Alliez, Leif Kobbelt
masonry On the Equilibrium of Simplicial Masonry Structures
Fernando de Goes, Pierre Alliez, Houman Owhadi and Mathieu Desbrun.
sgp13 Noise-Adaptive Shape Reconstruction from Raw Point Sets
EUROGRAPHICS Symposium on Geometry Processing 2013 (2nd Best Paper Award)
Computer Graphics Forum
Source code
Simon Giraudot, David Cohen-Steiner and Pierre Alliez.
eg2013 Surface Reconstruction through Point Set Structuring
Florent Lafarge and Pierre Alliez.
imr12 Anisotropic Rectangular Metric for Polygonal Surface Remeshing
Bertrand Pellenard, Jean-Marie Morvan and Pierre Alliez.
International Meshing Roundtable 2012
rr-2012 Feature-Preserving Surface Reconstruction and Simplification from Defect-Laden Point Sets.
Julie Digne, David Cohen-Steiner, Pierre Alliez, Mathieu Desbrun, Fernando de Goes.
Journal of Mathematical Imaging and Vision
Special issue for Mathematics and Image Analysis 2012
smi12 Progressive Compression of Manifold Polygon Meshes
Adrien Maglo, Clément Courbet, Pierre Alliez and Céline Hudelot.
Proceedings of Shape Modeling International 2012.
Source code
imr11 Isotropic 2D Quadrangle Meshing with Size and Orientation Control
Bertrand Pellenard, Pierre Alliez and Jean-Marie Morvan.
International Meshing Roundtable 2011
Abstract: We propose an approach for automatically generating isotropic 2D quadrangle meshes from arbitrary domains with a fine control over sizing and orientation of the elements. At the heart of our algorithm is an optimization procedure that, from a coarse initial tiling of the 2D domain, enforces each of the desirable mesh quality criteria (size, shape, orientation, degree, regularity) one at a time, in an order designed not to undo previous enhancements. Our experiments demonstrate how well our resulting quadrangle meshes conform to a wide range of input sizing and orientation fields.
sgp11 An Optimal Transport Approach to Robust Reconstruction and Simplification of 2D Shapes
Fernando de Goes, David Cohen-Steiner, Pierre Alliez, and Mathieu Desbrun.
Symposium on Geometry Processing, 2011.
Abstract: We propose a robust 2D shape reconstruction and simplification algorithm which takes as input a defect- laden point set with noise and outliers. We introduce an optimal-transport driven approach where the input point set, considered as a sum of Dirac measures, is approximated by a simplicial complex considered as a sum of uniform measures on 0- and 1-simplices. A fine-to-coarse scheme is devised to construct the resulting simplicial complex through greedy decimation of a Delaunay triangulation of the input point set. Our method performs well on a variety of examples ranging from line drawings to grayscale images, with or without noise, features, and boundaries.
pmp Polygon Mesh Processing (see also from amazon)
See also slides
Mario Botsch, Leif Kobbelt, Mark Pauly, Pierre Alliez and Bruno Levy.
AK Peters, ISBN 978-1-56881-426-1, 2010.
Abstract: Geometry processing, or mesh processing, is a fast-growing area of research that uses concepts from applied mathematics, computer science, and engineering to design efficient algorithms for the acquisition, reconstruction, analysis, manipulation, simulation, and transmission of complex 3D models. Applications of geometry processing algorithms already cover a wide range of areas from multimedia, entertainment, and classical computer-aided design, to biomedical computing, reverse engineering, and scientific computing. Over the last several years, triangle meshes have become increasingly popular, as irregular triangle meshes have developed into a valuable alternative to traditional spline surfaces. This book discusses the whole geometry processing pipeline based on triangle meshes. The pipeline starts with data input, for example, a model acquired by 3D scanning techniques. This data can then go through processes of error removal, mesh creation, smoothing, conversion, morphing, and more. The authors detail techniques for those processes using triangle meshes.

Students / post-docs / engineers
– 2018: Vasudha Varadarajan (intern from India, on binary reconstruction)
– 2018: Tong Zhao (intern from Ecole des Ponts, on geometric descriptors and spectral reconstruction)
– 2018: Flora Quilichini (PhD student on mesh compression)
– 2018: Fernando Ireta (post-doc on indoor localization and reconstruction)
– 2017: Leman Feng (intern from Ecole des Ponts on Higher order meshes)
– 2017: Vinay Datta Renigunta (Efficient solver for optimal transportation)
– 2017: Dmitry Anisimov (LOD reconstruction of urban scenes)
– 2017: Cédric Portaneri (Geometry compression)
– 2016: Come Le Breton (Mesh generation)
– 2015: Guillaume Matheron (intern from ENS Paris on optimal transportation)
– 2015: Maxim Torgonskiy (Mesh generation)
– 2015: Aditya Kusupati (IIT Bombay on anisotropic metrics)
– 2015; Mohammad Rouhani (post-doc on semantic classification)
– 2015: Emmanuel Maggiori (PhD student on classification of satellite images)
– 2015: Nicolas Douillet (culture 3D clouds)
– 2014: Jinjing Shen (visiting PhD student on isotropic meshing of NURBS surfaces)
– 2014: Devdeep Ray (intern on optimal transportation)
– 2014: Henrik Zimmer (post-doc)
– 2013: Renata Rego (post-doc on Robust feature extraction)
– 2013: Anmol Garg (Intern on Shape approximation)
– 2012: Kaimo Hu (post-doc on Robust surface remeshing)
– 2012: Thijs van Lankveld (Surface reconstruction for cultural heritage data)
– 2012: Clément Jamin (Parallel algorithms and shape detection)
– 2012: Yiyi Wei (Well-centered triangulations, co-advised with Mariette Yvinec)
– 2012: Manish Mandad (PhD on robust shape approximation with guarantees)
– 2012: Sven Oesau (Indoor scene reconstruction, co-advised with Florent Lafarge)
– 2012: David Bommes (Surface tiling)
– 2011: Xavier Rolland-Neviere (Watermarking of surface meshes, at Technicolor, co-advised with Gwenael Doerr)
– 2011: Simon Giraudot (Robust reconstruction of surfaces)
– 2011: Paul Seron (Reconstruction of urban scenes)
– 2011: Renata Nascimento (visiting PhD student on quadrangle surface tiling)
– 2011: Julie Digne (post-doc on robust shape reconstruction, now researcher at CNRS in Lyon)
– 2011: Sagar Chordia (shape approximation)
– 2010: Alain Tayeb (Meshing NURBS surfaces)
– 2010: Boris Dalstein (quadrangle surface tiling)
– 2009-present: Bertrand Pellenard (PhD on surface and domain tiling, defended Dec 18th 2012)
– 2009: Hugo Feree (ENS Lyon: probing implicit surfaces, now PhD student at Inria Nancy)
– 2009: Rahul Srinivasan (IIT Bombay: accelerating ODT mesh optimization and sliver removal)
– 2008: Amit Gupta (IIT Bombay: Poisson reconstruction for polygon soups)
– 2008: Saurabh Chakradeo (IIT Bombay: Fast intersections and projections for polyhedral surfaces)
– 2007: Ankit Gupta (IIT Bombay: PCA in CGAL and application to normal estimation), now at Stanford
– 2006-2009: Jane Tournois (PhD on mesh optimization), now at Geometry Factory.
– 2006: Lakulish Antani (IIT Bombay: mesh sizing using additively weighted Voronoi diagrams), now at UNC
– 2004: Abdelkrim Mebarki (master: placement of streamlines)
– 2004: Jérôme Gahide (progressive triangle mesh compression)
– 2003-2007: Marie Samozino (Ph.D.: reconstruction of surfaces from noisy point sets, co-advised with Mariette Yvinec), now Professor in Mathematics
– 2002: Mathieu Monnier (compression of 2D vectorial data)

Ecole des Ponts ParisTech
MASTER EPU Ingénierie 3D and Interpolation 3D


I am an avid user of the CGAL library. I am a CGAL editor and developer as well, implementing or participating to various projects: placement of streamlines from 2D vector fields, planar parameterization of triangle surface meshes, Principal Component Analysis, Surface reconstruction, Point Set Processing and 3D Isotropic Tetrahedron Mesh Generation and Optimization.

Current Projects
– ANR Pisco
– ANR Loca-3D
– ERC Proof of Concept TITANIUM
– Google Chrome University research program
Past Projects
EU ERC Starting grant IRON (Robust Geometry Processing)

Grand emprunt Investissements d’avenir: Culture 3D clouds
(national project about geometric inference and analysis)
ANR GYROVIZ (national project for reconstructing urban scenes from localized photos and videos)
Focus K3D (EU FP7 Coordination Action)
AIM@SHAPE (EU Network of Excellence)
– Full paper co-chair, EUROGRAPHICS conference.
Program co-chair, SPM conference.

– joined editorial board of Computer Graphics Forum for three years.
– programme committee: EUROGRAPHICS Symposium on Geometry Processing
– programme committee: International Conference on Geometric Modeling and Processing (GMP)
– programme committee: Shape Modeling International
– advisory committee: EUROGRAPHICS annual conference
– HDR committee: Stefanie Wuhrer (Inria Grenoble)
– Thesis committee: Arnaud Bletterer (I3S Sophia Antipolis)
joined the SMA Executive Board
– programme committee: ACM SIGGRAPH 2017
– programme committee: EUROGRAPHICS 2017
– programme committee: EUROGRAPHICS Star reports
– programme committee: EUROGRAPHICS Symposium on Geometry Processing
– programme committee: EG Workshop on Graphics and Cultural Heritage
– thesis reviewer: Giorgio Marcias (CNR Pisa, Italy)
– thesis reviewer: Claudio Calabrese (University Roma, Italy)
– thesis reviewer: Florian Caillaud (LIRIS Lyon)
– thesis reviewer: Dmitry Anisimov (Univ. Lugano)
– thesis reviewer: Yannick Masson (University Paris Est)
– thesis reviewer: Ana Vintescu (Telecom ParisTech)
– HDR committee: Maks Ovsjanikov (Ecole Polytechnique)

– programme committee: ACM SIGGRAPH 2016
– programme committee: EUROGRAPHICS 2016
– programme committee: Geometric Modeling and Processing 2016
– programme committee: Shape Modeling International 2016
– programme committee: EUROGRAPHICS Symposium on Geometry Processing
– programme committee: EUROGRAPHICS Workshop on Graphics & Cultural Heritage
– thesis reviewer: Ludovic Blache (CReSTIC-SIC Reims-Châlons-Charleville)
– thesis reviewer: Ruqi Huang (Inria Saclay)
– thesis reviewer: Li Wang (Inria Grenoble)
– thesis comittee: Mael Rouxel-Labbé (Inria)

– thesis reviewer: Jérémy Levallois (LIRIS)
– thesis committe: Rodolphe Vaillant (Université Paul Sabatier / University of Victoria)
– paper committee, EUROGRAPHICS Symposium on Geometry Processing (Graz, Austria)
– programme committee, Digital Heritage 2015
– thesis reviewer: Gilles-Philippe Paillé (Université de Montréal)

– thesis reviewer: Louis Cuel (Université de Savoie)
– thesis committee: Jean luc Peyrot (CNRS-Université de Nice)
thesis reviewer: Alexandre Boul’ch (Ecole des Ponts ParisTech)
– Joined Horizon 2020 Advisory Group for Societal Challenge 6 ‘Europe in a changing world – Inclusive, Innovative and Reflective Societies.
European paper co-chair, Geometric Modeling and Processing (Singapore)
– program committee, International Conference on 3D Computer Vision
– program committee, Shape Modeling International
thesis reviewer: Ricard Campos (University of Girona)
– joined the Steering Board of the EUROGRAPHICS Workshop on Graphics and Cultural Heritage
thesis reviewer: Henrik Zimmer (University of Aachen)
– program committe, EUROGRAPHICS Workshop on Graphics and Cultural Heritage
– paper committe, EUROGRAPHICS Workshop on Urban Data Modelling and Visualisation
– paper committee, EUROGRAPHICS Symposium on Geometry Processing (Cardiff, UK)
– thesis reviewer: Thierry Guillemot  (Telecom ParisTech)

paper committee, ACM Virtual Reality International Conference
– local board member for Digital Heritage 2013
– thesis committee: Ricardo Uribe-Lobello (LIRIS, CNRS Lyon)
– thesis committee: Yannick Verdie (Inria)
– thesis reviewer: Thijs van Lankveld (Utrecht)
– thesis committee: Yannick Verdie (Inria)
– thesis committee: Adrien Maglo (Centrale Paris)
– thesis committee: Noura Faraj (Telecom ParisTech)
– joined board of Computer Aided Geometric Design
paper committee, Shape Modeling International 2013
paper committee, Eurographics Symposium on Geometry Processing (Genova, Italy)
– habilitation thesis reviewer: Guillaume Lavoue (Universite de Lyon)

– thesis reviewer, Nicolas Mellado, (Inria Bordeaux)
– thesis reviewer, David Bommes (RWTCH Aachen)
– invited speaker, MICCAI workshop on Mesh Processing in Medical Image Analysis (Nice).
– invited speaker, 3DIMPVT: 3D Imaging, Modeling, Processing, Visualization and Transmission (Zurich).
– paper committee, EUROGRAPHICS conference (Cagliari, Italy)
– paper committee, Eurographics Symposium on Geometry Processing (Talinn, Estonia)
– program committee, International Workshop on Point Cloud Processing (in conjunction with CVPR)
– invited speaker, Advances in Architectural Geometry (Paris).

– thesis reviewer: Vincent Vidal (Universite de Lyon)
– habilitation thesis reviewer: Raphaelle Chaine (Universite de Lyon)
– thesis committee: Patrick Mullen (Caltech)
– programme committee, VAST International Symposium on Virtual Reality, Archaeology and Cultural Heritage
programme committee, Sibgrapi 2011
– paper committee, Eurographics Symposium on Geometry Processing
– programme committee, Shape Modeling International
– thesis reviewer: Clement Courbet (Ecole Centrale Paris)
– thesis committee: Marcio Cabral (INRIA Sophia)
– thesis reviewer: Sahar Hassan (University of Grenoble)

– joined board of Elsevier Graphical Models
– thesis reviewer: Julie Digne (ENS Cachan)
paper co-chair, Pacific Graphics 2010
– programme committee, Shape Modeling International
programme committee
, ACM Symposium on Solid and Physical Modeling
– paper committee, Eurographics Symposium on Geometry Processing
– scientific committee: Advances in Architectural Geometry
– thesis committee: Mathieu Bredif (Telecom ParisTech and IGN, France)
– thesis reviewer: Thierry Stein (INRIA Rhone Alpes)

– associate editor of the ACM Transactions on Graphics
short paper co-chair, Eurographics
programme committee, IMA Mathematics of Surfaces XIII conference.
programme committee, SIAM/ACM Joint Conference on Geometric and Physical Modeling
– paper committee, Eurographics Symposium on Geometry Processing
– paper committee, Pacific Graphics
– thesis reviewer: Patrick Labatut (ENS Paris)
– thesis committee: Jean-Marie Favreau (University of Clermont-Ferrand)
– thesis committee: Jane Tournois (INRIA Sophia)

paper co-chair, Eurographics Symposium on Geometry Processing
– paper committee, EUROGRAPHICS
– paper committee, Pacific Graphics
– paper committee, Shape Modeling International
– paper committee, ACm Symposium on Solid and Physical Modeling
– paper committee, Symposium on 3D Data Processing, Visualization and Transmission
– thesis reviewer: Christopher Dyken (University of Oslo)
– thesis reviewer: Johan Seland (University of Oslo)

– paper committee, SIGGRAPH
– paper committee, CAD/Graphics
– paper committee, Pacific Graphics
– paper committee, Shape Modeling International
– paper committee, ACM Symposium on Solid and Physical Modeling
– paper committee, Eurographics Symposium on Geometry Processing

paper committee, Pacific Graphics
– associate editor of the Visual Computer
– associate editor of Computers & Graphics
– part of the french ANR project GEOTOPAL
– thesis reviewer: Martin Marinov (RWTH Aachen)
– paper committee, ACM Symposium on Solid and Physical Modeling
paper committee
, Eurographics Symposium on Geometry Processing
paper committee, IEEE International Conference on Shape Modeling and Applications

– Video and Multimedia presentation program committee, SOCG 2005
– paper committee, EUROGRAPHICS
Symposium on Geometry Processing 2005
– paper committee, EUROGRAPHICS 2005
– paper committee, Pacific Graphics 2005
– thesis reviewer: Christian Rossl (MPII Saarbruck), Raphaele Balter (University of Rennes)
– member of thesis committee:Marie-Claude Frasson (University of Nice), Guillaume Lavoue (University of Lyon), Gabriel Peyre (Ecole Polytechnique)

– ACI GeoComp 2004-2007
AIM@SHAPE EU Network of Excellence (workpackage leader)

– organizing co-chair,
Second Eurographics Symposium on Geometry Processing 2004
– paper committee, Eurographics
Symposium on Geometry Processing 2004
– paper committee, Eurographics 2004
– paper committee, Pacific Graphics 2004
– paper committee, Shape Modeling International 2004
– member of thesis committee: Frederic Payan