/*! \page constructing_meshes_page Constructing meshes \n Construction of a mesh consists of: To construct a mesh:
  1. In the \b Mesh menu select Create Mesh or click "Create Mesh" button in the toolbar. \image html image32.png
    "Create Mesh" button
    The following dialog box will appear: \image html createmesh-inv.png
  2. For example, you need to mesh a 3d object. \n 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. \image html image120.png
    "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. \image html image121.png
    "Add Hypothesis" button
    Click the "Edit Hypothesis" button to define values for the current hypothesis. \image html image122.png
    "Edit Hypothesis" button
    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. \n In the Object Browser the structure of the new mesh will be displayed as follows: \image html image88.jpg 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.
    3. \anchor preview_mesh_anchor
  3. 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 \b Mesh menu select \b Preview or click "Preview" button in the toolbar or activate "Preview" item from the pop-up menu. \image html mesh_precompute.png
    "Preview" button
    Select 1D mesh or 2D mesh preview mode in the Preview dialog. \image html preview_mesh_1D.png "1D mesh preview shows nodes computed on geometry edges" \image html preview_mesh_2D.png "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: \image html preview_tmp_data.png These elenents can be reused in the next mesh computation.
  4. It is equally possible to skip the Preview and \b Compute the mesh after the hypotheses are assigned. For this, select your mesh in the Object Browser. From the \b Mesh menu select \b Compute or click "Compute" button of the toolbar. \image html image28.png
    "Compute" button
    The Mesh Computation information box appears. \image html meshcomputationsucceed.png If the mesh computation failed, the information about the cause of the failure is provided. \image html meshcomputationfail.png After you select the error, Show Subshape button allows visualizing the geometrical entity that causes it. \image html failed_computation.png "Example of the invalid input mesh" \note Mesh Computation Information box does not appear if you set "Mesh computation/Show a computation result notification" preference to the "Never" value. This option gives the possibility to control mesh computation reporting. There are the following possibilities: always show information box, only if an error occurs or never. By default, the information box is always shown after mesh computation operation. 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.
  5. It is possible to calculate the eventual mesh size before \b Compute operation. For this, select the mesh in the Object Browser and from the \b Mesh menu select \b Evaluate. The result of evaluation will be displayed in the following information box: \image html mesh_evaluation_succeed.png
\anchor mesh_order_anchor It is allowed to change submesh priority in mesh computation when there are concurrent submeshes present. I.e. user can change priority of applying algorithms on shared subshapes of Mesh shape. To change submesh priority:
  1. From the Mesh menu choose the "Change submesh priority" on selected Mesh item, or invoke from popup menu. The opened dialogue box shows a list of submeshes in the order of their priority. Algorithm and its hypotheses of a submesh being upper in the list are applied before those of a submesh lower in the list. There is an example of submesh order modifications of Mesh created on a Box shape. The main Mesh object: The first submesh object Submesh_1 created on Face_1 is: The second submesh object Submesh_2 created on Face_2 is: And the last third submesh object Submesh_3 created on Face_3 is: The submeshes can become concurrent if their algorithms leads to mesh shared subshape with different algorithms (or different algorithms parameters, i.e. hypothesises). In fact, we have three submeshes with concurrent algorithms, becase they has different hypothesises assigned to them. The first mesh computation made with: \image html mesh_order_123.png
    "Mesh order SubMesh_1, SubMesh_2, SubMesh_3"
    \image html mesh_order_123_res.png
    "Result mesh with order SubMesh_1, SubMesh_2, SubMesh_3 "
    The next mesh computation with: \image html mesh_order_213.png
    "Mesh order SubMesh_2, SubMesh_1, SubMesh_3"
    \image html mesh_order_213_res.png
    "Result mesh with order SubMesh_2, SubMesh_1, SubMesh_3 "
    And the last mesh computation with: \image html mesh_order_321.png
    "Mesh order SubMesh_3, SubMesh_2, SubMesh_1"
    \image html mesh_order_321_res.png
    "Result mesh with order SubMesh_3, SubMesh_2, SubMesh_1 "
    As we can see each mesh computation has different number of result elements and different mesh descretisation on shared edges (edges, that shared between Face_1, Face_2 and Face_3) Additionally, submesh priority (order of algorithms to be applied) can be modified not only in separate dialog box, but in Preview also. This helps to preview different mesh results, modifying submesh order. \image html mesh_order_preview.png
    "Preview with submesh priority list box"
    If no concurrent submeshes under Mesh object user will see the following information dialog box \image html mesh_order_no_concurrent.png
    "No concurrent submeshes detected"
    and no mesh order list box appear in Preview dialog box.
Consider trying a sample script for construction of a mesh from our \ref tui_creating_meshes_page "TUI Scripts" section. */