Mmg Day 2021

The 5th Mmg day will take place on Wednesday, December 8th, 2021, from 2pm to 5pm.

It will take place in hybrid mode (at the jussieu campus and via the zoom link provided at the end of this page) :

Jussieu campus,
4 place Jussieu,
75005 Paris (France),
Corridor 15-25, Room 104.

The registration is free but mandatory: Online registration form

The purpose of this event is to:

  • present news regarding the Mmg platform;
  • show different usage of the platform;
  • open the discussion on meshes issues and challenges;
  • foster exchanges between users of meshes and developers of meshing tools.

The Mmg day will be followed by the FreeFEM days!



13h45 – 14h00: Welcome

14h00 – 14h25: Mesh adaptation in unsteady simulations of turbulent flow. Guillaume Balarac (Univ. Grenoble Alpes, CNRS, Grenoble INP, LEGI UMR 5519)

Due to a large range of motion scales, turbulent flows are still challenging to simulate. Indeed, the mesh needs to be fine enough to capture, at least, the most relevant part of these scales when Large-Eddy Simulation (LES) approach is used. In this context, mesh adaptation is used with two main objectives. First, dynamic mesh adaptation (DMA) can be used to take into account complex configurations. This can be to take into account the presence of moving solid bodies, or even to simulate deformable bodies in the context of fluide-structure interaction. DMA can be also used to simulate multiphase flows to accurately describe the phases interface. The second objective is to guarantee the reliability of the simulations in a mesh verification process. For this purpose an automatic mesh convergence process has been developed to define an optimal mesh based on criteria given by the physics of turbulent flows.

14h25 – 14h50: PISCO : A R&D platform for optimal design. Chiara Nardoni (IRT SystemX, Palaiseau)

Topology optimization is devoted to the optimal design of structures. It aims at finding the best ma- terial distribution inside a working domain while fulfilling mechanical, geometrical and manufacturing specifications. The need for lighter and efficient parts and assemblies has made topology optimization a vigorous research field in both academic and industrial structural engineering communities. This contribution focuses on PISCO, a Research and Development software platform for shape and topology optimization where the computational process is carried out in a level set framework combined with a body-fitted approach. Since the structural interface is known explicitely at each step of the iterative procedure, the body-fitted approach simplifies the evaluation of the mechanical quantities of interest. PISCO comprises several components including an algorithmic toolbox specialized in the treatment of level sets, a generic interface to finite element solvers, a toolbox handling mesh files in several classical formats, several algorithms for the resolution of constrained optimization problems, physical and geometrical optimization criteria and an advanced interface to the remeshing tool mmg3d. The components devoted to the physical simulations and the constrained optimization algorithms are implemented in a generic fashion in dedicated modules. The actual coupling of PISCO with several external physical solvers demonstrates the practical benefits of the chosen weakly intrusive strategy. Industrial applications are presented to highlight the capabilities of the platform.

14h50 – 15h15: Mmg and FreeFEM: a 12+ year-old success story. Pierre Jolivet (Univ. Toulouse, IRIT-CNRS)
Mmg has been integrated in FreeFEM since 2009. Many things have changed since then, in particular when going from Mmg version 4 to Mmg version 5.
Recently, ParMmg has been integrated in FreeFEM as well. I will present the key points behind the integration of these two libraries in FreeFEM, and more recently, in PETSc as well.
Numerical results coming from various applications will be provided to show how unstructured mesh adaptation fits into the typical workflows of FreeFEM users.


15h15 – 15h30: Break

15h30 – 15h45: Mmg platform in few words. Algiane Froehly (Inria Bordeaux – Sud-Ouest, Pau)

The aim of this presentation is to introduce the Mmg platform, a platform dedicated to triangular and tetrahedral remeshing, and to present recent development and projects.

15h45 – 16h10: Meshing challenges for CO2 geological sequestration. Antoine Mazuyer (TotalEnergies, Paris – Saclay)

Geological sequestration of CO2 in quantity is one of the most promising methods to curb global warming. To achieve this goal, large volumes of CO2 has to be permanently stored into geological reservoirs. Modeling and simulating CO2 sequestration is a multi-disciplinary effort involving coupled physical and chemical phenomena. In this presentation, we present our work on the generation of meshes that support multiphysics numerical simulations, specifically focusing on flow and poromechanics couplings. Building models suited to multiphysics simulations is challenging because we need meshes that are suited to several types of numerical methods, and adapted to the vertical geological heterogeneities. To achieve that, we propose to use MMG in order to generate a tetrahedral mesh with an anisotropic mesh size.

16h10 – 16h35: New guarantees on mesh untangling. Dmitry Sokolov (Univ. Lorraine, LORIA, Inria, Vandoeuvre-les-Nancy)

Mapping a triangulated surface to 2D plane (or a tetrahedral mesh to 3D space) is the most fundamental problem in geometry processing. The critical property of a good map is a (local) invertibility, and it is not an easy one to obtain. We propose a mapping method inspired by the mesh untangling problem. In computational physics, untangling plays an important role in mesh generation: it takes a mesh as an input, and moves the vertices to get rid of foldovers. In fact, mesh untangling can be considered as a special case of mapping, where the geometry of the object is to be defined in the map space and the geometric domain is not explicit, supposing that each element is regular. This approach allows us to produce locally invertible maps, which is the major challenge of mapping. In practice, our method succeeds in very difficult settings, and with less distortion than the previous work, both in 2D and 3D.


16h35 – 17h00: Final Break


Zoom connexion details

link :

SIP protocol:

H.323 protocol (USA (West)) (USA (East)) (Mumbai – India) (Hyderabad – India) (Amsterdam Netherlands) (Germany) (Australia Sydney) (Australia Melbourne) (Singapore) (Brazil) (Mexico) (Canada Toronto) (Canada Vancouver) (Japan Tokyo) (Japan Osaka)

password: 098012
meeting id: 850 8259 6516

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