Thanks to user-defined macros, loops, conditionals, and includes (see User-defined macros, Loops and conditionals, and Other general commands), the built-in scripting language may easily express simple and/or “repetitive” geometries. Installing and running Gmsh on your computer Silent Features of Gmsh-:.The next section includes a brief summary of each of the four modules, a list of Gmsh’s strengths (and weaknesses), as well as instructions on how to install and use Gmsh on your machine. The tutorial source files, as well as many other examples, are available in the source code repository. Gmsh is composed of four modules (geometry, mesh, solver, and post-processing) that can be accessed via the graphical user interface, the command line, text files written in Gmsh’s own scripting language (.geo files), or the C++, C, Python, Julia, and Fortran application programming interface.įor a high-level overview of Gmsh, see this general presentation, and the reference manual for the complete documentation, which includes the Gmsh tutorial. Its design goal is to provide a meshing tool that is fast, light, and easy to use, with parametric input and versatile visualisation features. Gmsh is a free and open source 3D finite element mesh generator with a CAD engine and post-processor built in. GMSH has API to generate input file using Programming language Python and C++. The 2D/3D mesh generated can be converted into nodes, elements using GNU free tool GetDP. GMSH installation provides twenty-one examples covering all the features. Figure 2: Smooth curve to be fitted for the hand-drawn approximate curve ( Between Point 1 to 9)įigure 3: Bezier curve for Points 1 to 9 and Mesh Generation Comparison of Bezier, BSpline and Spline Figure 4: Comparision of three curves passing through given Input of points, Bezier, BSpline and Spline Example 3 Extrude function 2D Surface to 3D Curved Surface ( ring doughnut) Figure 5: Extrude Command to generate from 2D surface to ring doughnut surface GMSH Software and Further Readingįurther examples and descriptions of various commands can be found on the official GMSH page. In this example, a smooth curve is fit between the approximate position of points 1 to 8 drawn using a hand sketch. In this example, a square plate of dimension 2*a by 2*a with a central circular hole of radius ( variable radius) is generated as shown in Figure 1 below with an input file for GMSH (.geo file) Figure 1: 2D Mesh for Plate with Circular Hole ( Mesh size on four corner of square lc and at Circular hole lc1 Example 2 use of Bezier GMSH - Geometry Building Units Operations on Geometryīasic geometry building units can be further upgraded (point to line, line to surface and surface to volume) or modified using various operations (for example fillet edges, Boolean operation - interesting / union/difference ) as presented in the following figure Operations on Geometry Building Units Example 1 Lines/Curves are further grouped to define closed boundaries of 2D or curved surfaces. Points are joined to generated line and curve ( Bezier, B-Spline, Spline, Circle and Ellipse). Geometry is prepared using basic building units, Point. This makes it possible to automate geometry generation by changing the variables' values. Input files can be written using expressions, variables, and commands (conditional statements, loops, and various in-built mathematical functions). One more strength of GMSH is Parametric Input. It has the capability to generate 2D and 3D structured mesh and export files (Joint Coordinates, Element Incidences and Elements grouped based on physical naming) compatible with analysis software. This article gives features and uses of the mesh generation tool, GMSH. General-purpose analysis tools have limited capabilities for auto-mesh generation. ![]() FEA results correctness depends on mesh quality (aspect ratio, skewness, and element size distribution). Finite Element Analysis (FEA) has extensive applications in structural engineering (static analysis, dynamic analysis, fatigue analysis), fluid flow, wind engineering and Geotech ( slope stability, settlement).
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