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Example of usage mesh 3D algorithms and hypothesis

Example of usage mesh 3D algorithms and hypothesis

This sample is known to work on the latest SALOME release.
The compatibility with previous versions of SALOME is not guaranteed, though the sample can work on old versions also.

Objective

This exercise illustrates the use of SMESH SALOME 3D algorithms and hypothesis and functionalities for meshing of the prism shape.

Geometry

The sequence of actions is as follows:
  • Launch SALOME.
  • Create a new study.
  • Launch GEOM module.
  • Load script Prism.py (menu File/Load script)
  • Create group of faces Group_1: (menu New Entity/Group/Create Group)
    Check 3rd radio button of "Shape Type" - "Face”
    Select Main shape Prism_1
    Select 4 side Faces holding down the Shift key
    Click "Add"
    Apply and Close.

Construction and modification of the mesh

Launch SMESH module.
  • Creation of Mesh_1: (menu Mesh/Create Mesh)
    Geometry: Prism_1
    3D algorithm: Netgen 1D-2D-3D
    3D hypothesis: Netgen 3D parameters
    Max Size = 15
    Fineness - Moderate
    Uncheck “Second order”, “Optimize” check-boxes
    OK, Apply and Close
  • Compute Mesh_1
  • Controls/Volume Controls/Volumes
Netgen 1D-2D-3D algorithm does not require 2D and 1D algorithms and hypothesis. It creates tetrahedrons. Computed Mesh may to differ from the picture depending of algorithm Netgen.		 OCC6_screen2
  • Hide item in 3D Viewer from popup menu - Display entity/Faces
  • Select in 3D Viewer from popup menu - Clipping
    New -> Relative
    Orientation - ||X-Y
    Distance - 0.5
    Rotation around X (Y to Z) - 0
    Rotation around Y (X to Z) - 0
    Apply and Close
Clipping shows only part of mesh and permits to analyse mesh inside.		 OCC6_screen2
  • Edit Mesh_1: (menu Mesh/Edit Mesh/Sub-mesh)
    3D algorithm: Tetrahedron(Netgen)
    3D hypothesis: Max Element Volume = 100
    2D algorithm: Triangle Mefisto
    2D hypothesis: Max Element Area = 100
    1D algorithm: Wire Discretization
    1D hypothesis: Local length =20
    Apply and Close

  • Compute Mesh_1
Tetrahedron(Netgen) creates only tetrahedrons in this case.
OCC6_screen2
  • Creation of SubMesh_1: (menu Mesh/Create Sub-mesh)
    Geometry: Group_1 (side faces)
    2D algorithm: Quadrangle mapping
    Apply and Close

  • Compute Mesh_1
Tetrahedron(Netgen) together with Quadrangle mapping creates pyramids (external layer) and tetrahedrons.

  • Edit Mesh_1: (menu Mesh/Edit Mesh/Sub-mesh)
    3D algorithm: 3D extrusion
    Apply and Close
  • Compute Mesh_1
3D extrusion creates only prisms in this case.















  • Edit Mesh_1: (menu Mesh/Edit Mesh/Sub-mesh)
    3D algorithm: Hexahedron(I,j,k)
    2D algorithm: Quadrangle mapping
    1D algorithm: Wire Discretization
    1D hypothesis: Local length = 20
    Apply and Close

  • Compute Mesh_1
Existing 2D and 1D algorithms and hypothesis are used (do not create new). Hexahedron(I,j,k) creates hexahedrons and prisms in this case.


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