![]() In addition, the miniapp can save the loaded mesh in native MFEM and VTK formats. The input mesh can be in any format supported by MFEM. Here new_mesh_file.msh is the mesh file selected by the user. To operate on a different mesh, users should exit the miniapp with q and start it again with the following line. Saving the resulting mesh with in MFEM or VTK format with S and V.įor example, selecting v in the prompt and pressing enter will display the default mesh of a hex-meshed beam in the GLVis window. Quantitative and visual reports of mesh quality with x, h and J. The ability to simulate parallel partitioning with p. Manipulation of the mesh curvature with c. Mesh refinement with r, scaling with s, randomization with j, and transformation with t. Visualizing of mesh materials with m, and individual mesh elements with e. An example screenshot of provided belowīy pressing the corresponding keys, a number of operations can be performed on the input mesh files, including: Once started, many options will appear in the terminal window. mesh-explorerīefore executing it, users should ensure that the GLVis window is open and connected to the AWS machine. Once compiled, it can be executed in the same directory by typing in the terminal. Users have to compile it in the miniapps/meshing subdirectory: cd ~/mfem/miniapps/meshing The mesh explorer miniapp is a handy tool to examine, visualize and manipulate a given mesh. However, users are encouraged to also explore the other meshing miniapps. Below we provide more details about only two of these miniapps. ![]() The miniapp examples illustrate a large part of the MFEM functionality in the miniapps/meshing subdirectory. MFEM provides many tools, routines, and examples for mesh manipulation. However, this feature requires compilation of the library with HDF5, NetCDF, and Exodus, which is not available in the AWS tutorial image. MFEM can import meshes saved in Exodus II format generated with Cubit. However, the users will see only the defined physical surfaces (1,2) and the boundaries between the parallel partitions. The results can be seen in the GLVis windows as well. Executing the modified code with the newly created mesh will result in the following solution: In the above snippet, we project coefficient one on the degrees of freedom associated with physical surface 2 (the indexing starts at zero). zero, which satisfies the boundary conditions.Īrray ess_bdr(pmesh.bdr_attributes.Max()) Define the solution vector x as a parallel finite element grid Thus, in order to set it to one, modify section 10 in ex1p.cpp: // 10. If we run ex1.cpp without modifications, a zero value will be assigned to the newly defined surface. The line should be inserted in any place after the definition of geometrical surface 7, e.g., after the boolean operation defining the final geometry. The following snippet defines these objects: SetFactory("OpenCASCADE") Ĭylinder(2) = We will start with the definitions of a cube with edge length L=1 and two cylinders with a radius L/10 and heights equal to L. ![]() If Gmsh is not installed on your local machine, please download it and follow the installation instructions. Users familiar with Gmsh can skip the first steps and download already prepared geometries for meshing. Many examples together with documentation on the input syntax can be found at the Gmsh website. Here, however, we focus on simpler examples showing the process of generating meshes suitable for MFEM and not on the actual geometry. CAD models in IGES or STEP formats can be imported by the CAD engine of Gmsh, meshed, and prepared as inputs to the MFEM examples. The geometry can be generated using the Gmsh graphical user interface (GUI), simple text editors such as Vi/Vim/Emacs, or using more sophisticated CAD tools such as SolidWorks or Autocad. The input to Gmsh can be a simple text file that provides a description of the geometry of the finite element model. Gmsh is an open-source, freely available mesh generation tool with built-in computer-aided design (CAD) functionality and a postprocessor. ![]() In this section we demonstrate the common steps necessary for generating high-quality meshes in Gmsh and Cubit and how to use them in finite element simulations with MFEM. And Finite Element Basics pages before this lesson.
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