Meshing

This page provides a brief description of MFEM's mesh formats and meshing mini applications.

Mesh formats

MFEM supports a number of mesh formats, including:

• MFEM's mesh v1.0 format for straight meshes,
• MFEM's mesh v1.0 format for arbitrary high-order curvilinear and more general meshes,
• MFEM's mesh v1.1 format, which adds support for non-conforming (AMR) meshes,
• MFEM's mesh v1.2 format, which adds support for parallel meshes,
• MFEM's format for NURBS meshes,
• The VTK unstructured mesh format, for triangular, quadrilateral, tetrahedral and hexahedral meshes,
• The Gmsh ASCII and binary formats for 2D and 3D meshes.
• The CUBIT meshes through the Genesis (NetCDF) binary format.
• The NETGEN triangular and tetrahedral mesh formats,
• The TrueGrid hexahedral mesh format.

Detailed description of these formats can be found on the mesh formats page. These formats are also supported by MFEM's native visualization tool, GLVis.

Meshing miniapps

The miniapps/meshing directory contains a collection of meshing-related miniapps based on MFEM.

Compared to the example codes, the miniapps are more complex, demonstrating more advanced usage of the library. They are intended to be more representative of MFEM-based application codes. We recommend that new users start with the example codes before moving to the miniapps.

The current meshing miniapps are described below.

Mobius Strip

This miniapp generates various Mobius strip-like surface meshes. It is a good way to generate complex surface meshes.

Manipulating the mesh topology and performing mesh transformation are demonstrated. The mobius-strip mesh in the data directory was generated with this miniapp.

Klein Bottle

This miniapp generates three types of Klein bottle surfaces. It is similar to the mobius-strip miniapp.

The klein-bottle and klein-donut meshes in the data directory were generated with this miniapp.

Shaper

This miniapp performs multiple levels of adaptive mesh refinement to resolve the interfaces between different "materials" in the mesh, as specified by a given material() function.

It can be used as a simple initial mesh generator, for example in the case when the interface is too complex to describe without local refinement. Both conforming and non-conforming refinements are supported.

Mesh Explorer

This miniapp is a handy tool to examine, visualize and manipulate a given mesh.

Some of its features are:

• visualizing of mesh materials and individual mesh elements
• mesh scaling, randomization, and general transformation
• manipulation of the mesh curvature
• the ability to simulate parallel partitioning
• quantitative and visual reports of mesh quality

Mesh Optimizer

This miniapp performs mesh optimization using the Target-Matrix Optimization Paradigm (TMOP) by P.Knupp et al., and a global variational minimization approach.

It minimizes the quantity $\sum_T \int_T \mu(J(x))$, where $T$ are the target (ideal) elements, $J$ is the Jacobian of the transformation from the target to the physical element, and $\mu$ is the mesh quality metric.

This metric can measure shape, size or alignment of the region around each quadrature point. The combination of targets and quality metrics is used to optimize the physical node positions, i.e., they must be as close as possible to the shape / size / alignment of their targets.