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A sphere meshed by Body Fitting algorithm
+.. note:: The algorithm creates only 3D elements. To add 2D elements use :ref:`Generate boundary elements <make_2dmesh_from_3d_page>` operation.
+
The meshing algorithm is as follows.
#. Lines of a Cartesian structured grid defined by :ref:`Body Fitting Parameters <cartesian_hyp_anchor>` hypothesis are intersected with the geometry boundary, thus nodes lying on the boundary are found. This step also allows finding out for each node of the Cartesian grid if it is inside or outside the geometry.
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Implement Edges switched off to the left and on to the right
+* **Create Faces** check-box activates creation on mesh faces.
+* **Consider Shared and Internal Faces** check-box activates treatment of faces shared by solids and internal. By default the algorithm considers only outer boundaries of the geometry.
+* **Apply Threshold to Shared / Internal Faces** check-box activates application of **Threshold** to cells cut by shared and internal faces, that can cause appearance of holes inside the mesh.
* **Definition mode** allows choosing how Cartesian structured grid is defined. Location of nodes along each grid axis is defined individually:
* You can specify the **Coordinates** of grid nodes. **Insert** button inserts a node at **Step** distance (negative or positive) from the selected node. **Delete** button removes the selected node. Double click on a coordinate in the list enables its edition. **Note** that node coordinates are measured along directions of axes that can differ from the directions of the Global Coordinate System.
* You can define the **Spacing** of a grid as an algebraic formula *f(t)* where *t* is a position along a grid axis normalized at [0.0,1.0]. *f(t)* must be non-negative at 0. <= *t* <= 1. The whole extent of geometry can be divided into ranges with their own spacing formulas to apply; a t varies between 0.0 and 1.0 within each **Range**. **Insert** button divides a selected range into two. **Delete** button adds the selected sub-range to the previous one. Double click on a range in the list enables edition of its right boundary. Double click on a function in the list enables its edition.
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+.. note:: The actual grid spacing can slightly differ from the defined one. This is done for the best fitting of polyhedrons and for a better mesh quality on the interval boundaries. For example, if a constant **Spacing** is defined along an axis, the actual grid will fill the shape's dimension L along this axis with round number of equal cells: Spacing_actual = L / round( L / Spacing_defined ).
* **Fixed Point** group allows defining an exact location of a grid node in the direction defined by spacing. The following cases are possible:
