Construction of a mesh consists of:
To construct a mesh:
In the Mesh menu select Create Mesh or click "Create Mesh" button in the toolbar.
The following dialog box will appear:
For example, you need to mesh a 3d object.
First, type the name for your mesh in the "Name" box, by default, it is "Mesh_1". Then select the object you wish to mesh in the Object Browser and click the "Add" button.
Now you can define 1d Algorithm and 1d Hypotheses, which will be applied to the edges of your object. (Note that any object has edges, even if their existence is not apparent, for example, a sphere has 4 edges). Click the "Add Hypothesis" button to add a hypothesis.
Click the "Edit Hypothesis" button to define values for the current hypothesis.
The use of additional hypotheses is optional (i.e. you may leave "None" in this box).
Proceed in the same way with 2d and 3d Algorithms and Hypotheses, note that the choice of hypotheses depends on the algorithm. There must be one Algorithm and one or several Hypotheses for each dimension of your object, otherwise you will not get any mesh at all. Of course, if you wish to mesh a face, which is a 2d object, you don't need to define 3d Algorithm and Hypotheses.
In the Object Browser the structure of the new mesh will be displayed as follows:
It contains:
There is an alternative way to create a mesh on an object simply by clicking Assign a set of hypotheses button and selecting between Automatic Tetrahedralization or Hexahedralization. The program will automatically generate a 3D mesh with the most appropriate settings. In the same way you can apply this functionality for meshing 2D objects, in which case 3D algorithms are not applied.
After the mesh object is created and all hypotheses are assigned and before the mesh computation, it is possible to see the mesh preview.
For this, select the mesh in the Object Browser. From the Mesh menu select Preview or click "Preview" button in the toolbar or activate "Preview" item from the pop-up menu.
Select 1D mesh or 2D mesh preview mode in the Preview dialog.
1D mesh preview shows nodes computed on geometry edges
2D mesh preview shows edge mesh elements, computed on geometry faces
Compute button computes the whole mesh.
When the Preview dialog is closed, the question about the storage of temporarily created mesh elements appers:
These elenents can be reused in the next mesh computation.
It is equally possible to skip the Preview and Compute the mesh after the hypotheses are assigned. For this, select your mesh in the Object Browser. From the Mesh menu select Compute or click "Compute" button of the toolbar.
The Mesh Computation information box appears.
If the mesh computation failed, the information about the cause of the failure is provided.
After you select the error, Show Subshape button allows visualizing the geometrical entity that causes it.
Example of the invalid input mesh
Publish Subshape button publishes the subshape, whose meshing failed, in GEOM component as a child of the mesh geometry, which allows analyzing the problem geometry and creating a submesh on it in order to locally tune hypotheses.
NOTE It is possible to define a 1D or a 2D mesh in a python script and then use such submeshes in the construction of a 3D mesh. For this, there exist two algorithms: Use existing edges and Use existing faces. They are not entirely usable from the GUI, so a mesh created using these algorithms should be exported into a python script, edited and then imported into the GUi.
It is possible to calculate the eventual mesh size before Compute operation. For this, select the mesh in the Object Browser and from the Mesh menu select Evaluate. The result of evaluation will be displayed in the following information box:
Consider trying a sample script for construction of a mesh from our TUI Scripts section.