.. role:: blue
   :class: blue

Constructing Triangulation for a Face
=====================================
.. _Constructing_Triangulation_for_a_Face_:

.. kernel version: 

The method

.. code-block:: cpp

   void CalculateGrid( const MbFace &     face,
                       const MbStepData & stepData,
                             bool         edgePoints,
                             MbGrid &     grid,
                             bool         dualSeams = true );

approximates a face with triangular and quadrilateral plates.

The input parameters of the method are:

- *face* – face;
- *stepData* – data for calculating the approximation step;
- *edgePoints* – flag for using spatial points;
- *dualSeams* – flag for seam processing.

The output parameter of the method is the triangulation *grid*.

The method is declared in the *tri_face.h* file.

The *stepData* parameter controls the density of the triangulation and contains data for calculating the step when moving along the face surface. The *stepData* parameter is described in the subsection :ref:`Triangulation Calculation Control <Triangulation_Calculation_Control_>`. For different values of *stepData.stepType*, different triangulation data of *grid* are filled. If *stepData.stepType* contains the *ist_MipStep* mask, the *grid.params* set is filled. If *stepData.stepType* contains the *ist_CollisionStep* or *ist_ParamStep* mask, the *grid.params*, *grid.points* and *grid.normals* sets are filled. In all other cases, the *grid.params* and *grid.points* sets are filled.

Fig. 1 shows a triangulation of a planar face with the *ist_SpaceStep* mask:

.. figure:: ../../pictures/R.1.5.1.png
   :width: 9cm
   :align: center

   Fig. 1

Fig. 2 shows a triangulation of a curved face with the *ist_SpaceStep* mask.

.. figure:: ../../pictures/R.1.5.2.png
   :width: 9cm
   :align: center

   Fig. 2

This method is called when constructing polygonal objects by the :blue:`CalculateMesh`\() and :blue:`AddYourMesh`\() methods if *note.grid* == true.