Netgen 2D Parameters and Netgen 3D Parameters hypotheses work only with Netgen 1D-2D, Netgen 2D, Netgen 1D-2D-3D and Netgen 3D algorithms. Netgen 1D-2D and Netgen 1D-2D-3D algorithms do not require definition of lower-level hypotheses and algorithms (2D and 1D for meshing 3D objects and 1D for meshing 2D objects).
Dialog boxes of Netgen 1D-2D and Netgen 1D-2D-3D algorithms
Dialog boxes of Netgen 2D and Netgen 3D algorithms
- Name - allows to define the name for the algorithm (Netgen 2D (or 3D) Parameters by default).
- Max Size - maximum linear dimensions for mesh cells.
- Min Size - minimum linear dimensions for mesh cells. It is ignored if it is more than Max Size.
- Second Order - if this box is checked in, the algorithm will create second order nodes on the mesh, which actually will become Quadratic.
- Fineness - ranging from Very Coarse to Very Fine allows to set the level of meshing detalization using the three parameters below. You can select Custom to define them manually.
- Growth rate - allows to define how much the linear dimensions of two adjacent cells can differ (i.e. 0.3 means 30%).
- Nb. Segs per Edge and Nb Segs per Radius - allows to define the minimum number of mesh segments in which edges and radiuses will be split.
- Allow Quadrangles - allows to use quadrangle elements in a triangle 2D mesh. This checkbox is not present in Netgen 3D parameters because currently building a tetrahedral mesh with quadrangle faces is not possible.
- Optimize - if this box is checked in, the algorithm will try to create regular (possessing even sides) elements.
- Local sizes - allows to define size of elements on and around specified geometrical edges and vertices. To define the local size it is necessary to select a geometrical edge or vertex in the object browser or in the viewer, and to click On Edge or On Vertex correspondingly. Name of the geometrical object and a default Value will be added in the table where the Value can be changed.
- Remove - deletes a selected row from the table.
Netgen 2D simple parameters and Netgen 3D simple parameters allow defining the size of elements for each dimension.
1D group allows defining the size of 1D elements in either of two ways:
- Number of Segments has the same sense as Number of segments hypothesis with equidistant distribution.
- Local Length has the same sense as Local Length hypothesis.
2D group allows defining the size of 2D elements
- Length from edges if checked in, acts like Length from Edges hypothesis, else
- Max. Element Area defines the maximum element area like Max Element Area hypothesis.
- Allow Quadrangles - allows to use quadrangle elements in a triangle 2D mesh. This checkbox is not present in Netgen 3D simple parameters because currently building a tetrahedral mesh with quadrangle faces is not possible.
3D groups allows defining the size of 3D elements.
- Length from faces if checked in, the area of sides of volumic elements will be equal to an average area of 2D elements, else
- Max. Element Volume defines the maximum element volume like Max Element Volume hypothesis.
- Note
- Netgen algorithm does not strictly follow the input parameters. The actual mesh can be more or less dense than required. There are several factors in it:
- NETGEN does not actually use "NbOfSegments" parameter for discretization of edge. This parameter is used only to define the local element size (size at the given point), so local sizes of adjacent edges influence each other.
- NETGEN additionally restricts the element size according to edge curvature.
- The local size of edges influences the size of close triangles.
- The order of elements and their size in the 1D mesh generated by NETGEN differ from those in the 1D mesh generated by Regular_1D algorithm, resulting in different 2D and 3D meshes.