X-Git-Url: http://git.salome-platform.org/gitweb/?a=blobdiff_plain;f=doc%2Fsalome%2Fgui%2FNETGENPLUGIN%2Finput%2Fnetgen_2d_3d_hypo.doc;h=cf9c245412a452441ecbae586923967e8f103e4d;hb=1ea8c2828e8ebcfcff032c29aae4fbcc2ad42693;hp=8cc306e08d41ec41036b57be2b6838a9145795b1;hpb=2b9909cbae6ce6a3f1abf26e170c8ff1a3ee2b7c;p=plugins%2Fnetgenplugin.git diff --git a/doc/salome/gui/NETGENPLUGIN/input/netgen_2d_3d_hypo.doc b/doc/salome/gui/NETGENPLUGIN/input/netgen_2d_3d_hypo.doc index 8cc306e..cf9c245 100644 --- a/doc/salome/gui/NETGENPLUGIN/input/netgen_2d_3d_hypo.doc +++ b/doc/salome/gui/NETGENPLUGIN/input/netgen_2d_3d_hypo.doc @@ -10,13 +10,13 @@ hypotheses and algorithms (2D and 1D for meshing 3D objects and 1D for meshing 2D objects). \image html netgen2d3d.png -
Dialog boxes of Netgen 1D-2D and Netgen -1D-2D-3D algorithms
+
Hypothesis dialog boxes of Netgen 1D-2D and Netgen + 1D-2D-3D algorithms are same

\image html netgen2d3d_only.png
Dialog boxes of Netgen 2D and Netgen 3D -algorithms
+ algorithms - Name - allows to define the name for the algorithm (Netgen 2D (or 3D) Parameters by default). @@ -24,21 +24,36 @@ algorithms - 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 will then 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. +create second order mesh. +- Fineness - ranging from Very Coarse to Very Fine +allows to set the level of meshing detalization using the three +parameters below. You can select \a 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. +two adjacent cells can differ (e.g. 0.3 means 30%). +- Nb. Segs per Edge - allows to define the minimum number of +mesh segments in which edges will be split. This parameter is used +only if Limit Size by Surface Curvature is checked. +- Nb Segs per Radius - allows to define the size of +mesh segments and mesh faces in which curved edges and surfaces will +be split. This value divided by a radius of curvature gives an element +size at a given point. This parameter is used only if Limit Size by + Surface Curvature is checked. +- Limit Size by Surface Curvature - if this box is checked in, +then size of mesh segments and mesh faces on curved edges and surfaces +is defined using value of Nb Segs per Radius parameter, and +number of segments on straight edges is defined by values of +Nb. Segs per Edge parameter. If this box is not checked in, +then size of elements is defined by three parameters only: +Max Size, Min Size and Growth rate. +- Allow Quadrangles - if this box is checked in, the mesher +tries to generate quadrangle 2D mesh. Triangle elements are created +where quadrangles are not possible. +- Optimize - if this box is checked in, the algorithm will modify +initially created mesh in order to improve quality of elements. Optimization +process is rather time consuming comparing to creation of initial mesh. +- Fuse Coincident Nodes on Edges and Vertices - allows merging +mesh nodes on vertices and edges which are geometrically coincident +but are topologically different. \image html netgen3d_local_size.png @@ -60,42 +75,34 @@ dimension. \b 1D group allows defining the size of 1D elements in either of two ways: - Number of Segments allows specifying number of segments, that will split each edge, with equidistant distribution. -- Local Length can be applied for meshing of edges -composing geometrical object. Definition of this hypothesis -consists of setting required \b length of segments. +- Local Length defines length of segments. \b 2D group allows defining the size of 2D elements -- Length from edges if checked in, hypothesis forces building of -2D mesh segments having a length calculated as an average edge length +- Length from edges if checked in, size of +2D mesh elements is defined as an average mesh segment length for a given wire, else - Max. Element Area specifies expected maximum element area for each 2d element. -- 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. +- Allow Quadrangles - allows to generate quadrangle elements +wherever possible. \b 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 specifies expected maximum element volume -of each 3d element. +of 3d elements. \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 does not actually use Number of Segments 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 +close 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 local size of segments 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. -\note In the case where two points are geometrically confounded, a single node is generated. - */ - -