.. role:: blue
   :class: blue

Constructing a Symmetrical Body
================================
.. _Constructing_a_Symmetrical_Body_:


.. версия ядра: 118041


The function


.. code-block:: cpp

   MbResultType SymmetrySolid(       MbSolid &               solid,
                                     MbeCopyMode             sameShell,
                               const MbSymmetrySolidParams & symParams,
                                     c3d::SolidSPtr &        result );


constructs a symmetrical body with a given symmetry plane.

The input parameters of the function are:

- **solid** -- the original body;
- **sameShell** -- the copying mode of the original body;
- **symParams** -- the parameters of the operation.

The output parameter of the function is the constructed body **result**.

The function returns an operation result code from the :blue:`MbResultType` enumeration.

The function is declared in the *action_solid.h* file.

The parameter **sameShell** can take one of four values:

- *cm_Same* = 0 (the shell is not copied);
- *cm_KeepHistory* (the original shell and its copy have common base surfaces, vertices and faces unchanged by the operation);
- *cm_KeepSurface* (the original shell and its copy have common base surfaces);
- *cm_Copy* (the original shell and its copy have no common data).

The enumeration :blue:`MbeCopyMode` is described in section :ref:`Copying a Set of Faces MbFaceShell <Copying_a_Set_of_Faces_>`.

In the :blue:`MbSymmetrySolidParams` class, the following constructor is defined to initialize the object **symParams** (see *op_shell_parameter.h*):

.. code-block:: cpp

   MbSymmetrySolidParams( const MbPlacement3D & place,
                          const MbSNameMaker &  operNames,
                                ThreeStates     side );

where

- **place** -- the local coordinate system;
- **side** -- the retained part of the original body relative to the symmetry plane (+1 for the part above the plane, -1 for the part below the plane);
- **operNames** -- the namer for faces, edges and vertices of the constructed body.

If the parameter **symParams**.\ *side* = 1, the function creates a symmetrical body with respect to the specified symmetry plane as follows: the source body is cut by the XY-plane of the local coordinate system, the part of the source body located in the positive direction of the Z-axis from this plane is taken, a mirror copy of the selected part of the source body is constructed and then united with the selected part.

If **symParams**.\ *side* = -1, the function unites the part of the source body located in the negative direction of the Z-axis from the XY-plane of the local coordinate system with the mirror copy of this part with respect to the symmetry plane.

The parameter **operNames** provides naming for faces, edges and vertices of the constructed body.

Fig. 1 shows the original body **solid** and the symmetry plane **place**:

.. figure:: /MODELER/OPERATIONS_ON_BODIES/pictures/M.2.9.1.png
   :width: 9cm
   :align: center

   Fig. 1

Fig. 2 shows the constructed body **result**:

.. figure:: /MODELER/OPERATIONS_ON_BODIES/pictures/M.2.9.2.png
   :width: 11cm
   :align: center

   Fig. 2

Fig. 3 shows the constructed body **result** for a symmetry plane with opposite normal:

.. figure:: /MODELER/OPERATIONS_ON_BODIES/pictures/M.2.9.3.png
   :width: 9cm
   :align: center

   Fig. 3

Fig. 4 shows the original body **solid** and the symmetry plane **place**, which do not intersect:

.. figure:: /MODELER/OPERATIONS_ON_BODIES/pictures/M.2.16.1.png
   :width: 9cm
   :align: center

   Fig. 4

Fig. 5 shows the original body **solid** and the constructed mirror body **result**:

.. figure:: /MODELER/OPERATIONS_ON_BODIES/pictures/M.2.16.2.png
   :width: 12cm
   :align: center

   Fig. 5

The function :blue:`SymmetrySolid`\() adds to the operation log of the constructed body the builder :blue:`MbSymmetrySolid`, which contains all necessary data for performing the operation. The builder :blue:`MbSymmetrySolid` is declared in the file *cr_symmetry_solid.h*.

In the test application *test.exe*, constructing a symmetrical body is performed using the menu command "Create→Solid→Based on a solid→Symmetric".