3 \page cartesian_algo_page Body Fitting 3D meshing algorithm
5 Body Fitting algorithm generates hexahedrons of a Cartesian grid in
6 the internal part of geometry and polyhedrons and other types of
7 elements at the intersection of Cartesian cells with the geometrical
10 \image html cartesian3D_sphere.png "A shpere meshed by Body Fitting algorithm"
12 The meshing algorithm is as follows.
14 <li> Lines of a Cartesian structured grid defined by
15 \ref cartesian_hyp_anchor "Body Fitting Parameters" hypothesis are
16 intersected with the geometry boundary, thus nodes lying on the
17 boundary are found. This step also allows finding out for each node of
18 the Cartesian grid if it is inside or outside the geometry. </li>
19 <li> For each cell of the grid, check how many of its nodes are outside
20 of the geometry boundary. Depending on a result of this check
22 <li> skip a cell, if all its nodes are outside </li>
23 <li> skip a cell, if it is too small according to <b> Size
24 Threshold </b> parameter</li>
25 <li> add a hexahedron in the mesh, if all nodes are inside </li>
26 <li> add a polyhedron or another cell type in the mesh, if some
27 nodes are inside and some outside. </li>
31 To apply this algorithm when you define your mesh, select <b>Body
32 Fitting</b> in the list of 3D algorithms and click <em> "Add
33 Hypothesis" </em> button and <em>"Body Fitting Parameters"</em>" menu
34 item. Dialog of <b>Body Fitting Parameters
35 hypothesis</b> will appear.
38 \anchor cartesian_hyp_anchor
39 <h2>Body Fitting Parameters hypothesis</h2>
41 \image html cartesian3D_hyp.png "Body Fitting Parameters hypothesis dialog"
43 This dialog allows to define
45 <li>\b Name of the algorithm </li>
46 <li> Minimal size of a cell truncated by the geometry boundary. If the
47 size of a truncated grid cell is \b Threshold times less than a
48 initial cell size, then a mesh element is not created. </li>
49 <li> Cartesian structured grid. Each grid axis is defined
50 individually. <b> Definition mode </b> chooses a way of grid
52 <li> You can specify the \b Coordinates of grid nodes. \b Insert button
53 inserts a node at distance \b Step (negative or positive) from a
54 selected node. \b Delete button removes a selected node. Double
55 click on a coordinate in the list enables its edition. A grid
56 defined by \b Coordinates should enclose the geometry, else the
57 algorithm will fail. </li>
58 <li> You can define the \b Spacing of a grid as an algebraic formula
59 <em>f(t)</em> where \a t is a position along a grid axis
60 normalized at [0.0,1.0]. The whole range of geometry can be
61 divided into sub-ranges with their own spacing formulas to apply;
62 \a t varies between 0.0 and 1.0 within each sub-range. \b Insert button
63 divides a selected range into two ones. \b Delete button adds the
64 selected sub-range to the previous one. Double click on a range in
65 the list enables edition of its right boundary. Double click on a
66 function in the list enables its edition.
72 <b>See Also</b> a sample TUI Script of a
73 \ref tui_cartesian_algo "Usage of Body Fitting algorithm".