.. role:: blue
   :class: blue

Stiching Body Faces
===================
.. _Stiching_Body_Faces_:

.. kernel version: 118041

.. code-block:: cpp

   MbeStitchResType StitchShells( const c3d::SolidsSPtrVector & initialSolids,
                                  const MbShellStitchParams &   stitchParams,
                                        c3d::SolidSPtr &        resultSolid );

performs stitching of interlocking faces of several solids into one solid (the face orientation can be changed). The function is declared in the file *action_shell.h.*

The input parameters of the function are:

**initialSolids** - set of solids for stitching;

**stitchParams** - shell stitching parameters, which include the following:

- **_nameMaker** is the operation's namer;
- **_stitchAccuracy** is the stitching accuracy (accuracy of finding paired edges);
- **_formSolidBody** is the flag of forming a solid from a resulting shell;
- **_mergeEdges** is the merging of similar edges (true).

The output parameter of the method is the constructed solid or the shell **resultSolid** (depending on the **_formSolidBody** flag). If the parameter **_formSolidBody** = *true*, the constructed solid **resultSolid** is checked for absence of boundary edges, nested shells are searched and internal shells are reoriented if necessary. If the parameter **_formSolidBody** = *false*, then boundary edges are allowed in the constructed **resultSolid** solid, and the definition of shell nesting is not performed.

The function returns the operation result code from the :ref:`MbeStitchResType <MbeStitchResType_>` enumeration (see *mb_operation_result.h*):

- **stch_Success** --- the operation was completed successfully.
- **stch_PrepareError** --- error when preparing a stitching operation.
- **stch_CoorientFaceError** --- unable to set coordinated orientation of faces.
- **stch_SomeEdgesUnstitched** --- some edges are still unstitched.
- **stch_OutwardOrientError** --- failed to set face normals to the outside of the solid;
- **stch_NoEdgeWasStitched** --- no edges were stitched.
- **stch_SeparatePartsResult** --- there are still unconnected pieces after stitching;
- **stch_EdgeStitchError** --- error of the edge stitching.
- **stch_InputTopologyError** --- critical topology errors in input shells.

The function searches pairs of boundary edges that correspond to each other in length and location, and constructs the intersection curve of faces of the found edge in the given area. After successful construction of the intersection curve, a pair of boundary edges is replaced by a single edge connecting adjacent faces of the solids. If necessary, the function reorients the outer side of some faces. The set **initialSolids** can contain any finite number of solids.

Figure 1 shows two stitchable solids - **solids** \[0\] и **solids** \[1\]. Figure 2 shows the constructed solid **resultSolid**:

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.13.1.png
   :width: 12cm
   :align: center

   Fig. 1

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.13.2.png
   :width: 12cm
   :align: center

   Fig. 2

The :blue:`StitchShells`\() function adds the :blue:`MbStitchedSolid` builder to the built solid log, which contains all the necessary data for the solid building. The :blue:`MbStitchedSolid` builder is declared in the *cr_stitch_solid.h* file.