# Netgen 2D and 3D hypotheses

Netgen 2D and Netgen 3D hypotheses work only with Netgen 1D-2D and Netgen 1D-2D-3D algorithms. These algorithms do not require definition of lower-level hypotheses and algorithms (2D and 1D for meshing 3D objects and 1D for meshing 2D objects). They prove to be useful if lower-level meshing is homogeneous for all wires and faces of the meshed object.

- Name - allows to define the name for the algorithm (Netgen 2D (or 3D) Parameters by default)

- Max Size - maximum linear dimensions for mesh cells.

- 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.