.. role:: blue
   :class: blue


Constructing an Extrusion Body
==============================
.. _Constructing_an_Extrusion_Body_:

.. kernel version: 118041

The function

.. code-block:: cpp

   MbSweptData ExtrusionSolid( const MbSweptData &           sweptData,
                               const MbVector3D &            direction,
                               const MbSolid *               solid1,
                               const MbSolid *               solid2,
                                     bool                    checkIntersection,
                               const ExtrusionValues &       params,
                               const MbSNameMaker &          operNames,
                                     PArray<MbSNameMaker> &  contoursNames,
                                     MbSolid *&              result );


constructs an extrusion body.

The input parameters of the function are:

- **sweptData** – a parameter that contains data about a generatrix curve.
- **direction** – the extrusion direction.  
- **solid1** – used when the :blue:`MbSweptWay::sw_shell` option is selected, for extrusion up to the nearest faces of a given body in the forward direction.
- **solid2** – used when the :blue:`MbSweptWay::sw_shell` option is selected, for extrusion up to the nearest faces of a given body in the reverse direction.
- **checkIntersection** – a flag for uniting the **solid1** and **solid2** bodies with intersection checking.
- **params** – an object of the :blue:`ExtrusionValues` class that contains information on how the extrusion magnitude in each direction is defined (by distance, up to a surface, up to a body).
- **operNames** – the operation name maker.
- **contoursNames** – the name makers of the segments of the generatrix contour.

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

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

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

An extrusion body belongs to a type of swept bodies obtained by moving a generatrix curve along a guide curve. The guide curve of an extrusion body is a line segment. The extrusion body is constructed by moving one or several curves along a segment whose direction is defined by the **direction** vector.

The **sweptData** parameter contains information about the generatrix curves. The :blue:`MbSweptData` and :blue:`ExtrusionValues` classes are described in the *op_swept_parameter.h* file. 

The generatrix curve of an extrusion, revolution, or kinematic operation may include a set of two-dimensional contours, a set of three-dimensional contours, a wireframe, or a body. 

Two-dimensional contours on a surface may intersect. Closed intersecting contours are united using a Boolean operation on regions (Fig. 1). 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/Constructing_an_Extrusion_Body_1.png
   :width: 18cm
   :align: center

   Fig. 1

In the case of constructing an open shell, if an open contour is among the intersecting contours, then a shell with intersecting parts will be constructed and the function will return an error. 

In the case of constructing a closed shell, intersections of shells obtained from open contours are processed by a Boolean operation on shells.

For a set of two-dimensional contours on a surface, the following constraints apply:

- There may be one or several contours.
- If there are several contours, they must be either all closed or all open.
- If the contours are closed, they may be nested inside each other, and the nesting depth is not limited.

For two-dimensional contours on a non-planar surface, there is an additional constraint: all contours must be closed.

Construction of the operation based on two-dimensional contours on a non-planar surface assumes that the user specifies a body face as a generatrix. In this case, data for the generatrix can be obtained using the :blue:`MbFace::GetSurfaceCurvesData`\() face method. This method returns a copy of the base surface of the face and a set of two-dimensional contours created from edge loops.

The constraint for three-dimensional contours is that constructing a closed body by extruding a three-dimensional contour is possible only for a thin-walled variant.

When both a body and a surface are specified at the same time, it is assumed that a kinematic operation is performed on the body along a curve on this surface, with the motion being aligned with the normal.

The body construction may be performed in the forward direction relative to the **direction** vector, in the reverse direction relative to the **direction** vector, or in both directions. The construction parameters in each direction are defined by :blue:`MbSweptSide` objects.

The **params** parameter contains information about the extrusion method in the forward direction :blue:`MbSweptSide` **side1** and about the extrusion method in the reverse direction :blue:`MbSweptSide` **side2**. Extrusion in each direction can be carried out in three ways: 

1. If **way** = *sw_scalarValue*, the extrusion is performed over the length *scalarValue* in the **side1** or **side2** direction. 
2. If **way** = *sw_shell*, the extrusion is performed up to the nearest **solid1** or **solid2** object. 
3. If **way** = *sw_surface*, the extrusion is performed up to the **side1**.\ *surface* or **side2**.\ *surface* surface if **side1**.\ *distance* equals zero or **side2**.\ *distance* equals zero, respectively. 

If **way** = *sw_surface* and **distance** is not equal to zero, the extrusion is performed up to a surface equidistant from **side1**.\ *surface* or up to a surface equidistant from **side2**.\ *surface*, respectively. 

If **side1**.\ *rake* is not equal to zero or **side2**.\ *rake* is not equal to zero, the extrusion is performed with a draft **side1**.\ *rake* or **side2**.\ *rake* in the corresponding direction. 

The **params**.\ *thickness1* parameter defines the offset outward from the generatrix curve, and the **params**.\ *thickness2* parameter defines the offset inward from the generatrix curve. 

The **params**.\ *shellClosed* parameter controls whether the constructed body is closed. 

The **params**.\ *checkSelfInt* parameter indicates the need to check the construction result for self-intersection. By default, **params**.\ *checkSelfInt* = *false*, and the check is not performed.

The **mergeFlags** control flags manage the merging of similar faces or edges (*mergeFaces* = *true* – merge similar faces; *mergeEdges* = *true* – merge similar edges).

Fig. 2 shows the data used in construction and the inheritance scheme of extrusion body construction parameters :blue:`ExtrusionValues` & **params**.

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/inheritance_scheme.png
   :width: 18cm
   :align: center

   Fig. 2

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

Fig. 3 shows a two-dimensional contour **contour** and a planar surface **surface** (:blue:`MbPlane`).

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.2.png
   :width: 18cm
   :align: center

   Fig. 3

Fig. 4 shows a closed body constructed by extrusion using the specified parameters of the contour shown in Fig. 3. Each segment of the contour corresponds to a face of the body, whose name is taken from the respective element of the name generator **contoursNames**\[0\]. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.3.png
   :width: 18cm
   :align: center

   Fig. 4

Fig. 5 shows a closed thin-walled body constructed by extrusion using the specified parameters of the contour shown in Fig. 3. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.4.png
   :width: 18cm
   :align: center

   Fig. 5

Fig. 6 shows an open body constructed by extrusion using the specified parameters of the contour shown in Fig. 3. The construction parameters of the body shown in Fig. 4 differ from those of the body shown in Fig. 6 only by the **params**.\ *shellClosed* value. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.5.png
   :width: 18cm
   :align: center

   Fig. 6

Fig. 7 shows a two-dimensional contour **contour**, a planar surface **surface** (:blue:`MbPlane`), and two bodies **solid1** and **solid2** that will be used in the extrusion body construction. For the construction, the **solid1** and **solid2** bodies must completely cover the path of contour motion in the corresponding direction. At the same time, the **params**.\ *side1.rake*, **params**.\ *side2.rake*, **params**.\ *thickness1*, and **params**.\ *thickness2* parameters must be taken into account. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.6.png
   :width: 15cm
   :align: center

   Fig. 7

Such a construction is performed by extruding the contour to a length exceeding the maximum distance to the specified body, followed by subtracting the specified body from the constructed body. 

Fig. 8 shows a body constructed by extruding the contour shown in Fig. 7, with the “Up to nearest objects” options, where the **solid1** and **solid2** bodies are specified as such objects. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.7.png
   :width: 15cm
   :align: center

   Fig. 8

Fig. 9 shows a thin-walled body with drafted faces constructed by extruding the contour shown in Fig. 7, with the “Up to nearest objects” options, where the **solid1** and **solid2** bodies are specified as such objects. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.8.png
   :width: 15cm
   :align: center

   Fig. 9

Fig. 10 shows a two-dimensional contour **contour**, a planar surface **surface** (:ref:`MbPlane <MbPlane_Plane_>`) and two surfaces **surface1** and **surface2** that will be used in the extrusion body construction. For the construction, the **surface1** and **surface2** surfaces must completely cover the path of contour motion in the corresponding direction. At the same time, the **params**.\ *side1.rake*, **params**.\ *side2.rake*, **params**.\ *thickness1*, and **params**.\ *thickness2* parameters must be taken into account. The extrusion body is cut by the specified surfaces or by surfaces equidistant from them if **params**.\ *side1.distance* or **params**.\ *side2.distance* are not equal to zero. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.9.png
   :width: 15cm
   :align: center

   Fig. 10

Fig. 11 shows a body constructed by extruding the contour shown in Fig. 10, with the “Up to surface” options, where **surface1** and **surface2** are specified. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.10.png
   :width: 15cm
   :align: center

   Fig. 11

Fig. 12 shows a thin-walled body with drafted faces constructed by extruding the contour shown in Fig. 10, with the “Up to surface” options, where **surface1** and **surface2** are specified. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.11.png
   :width: 15cm
   :align: center

   Fig. 12

A two-dimensional contour may lie on a planar or a curved surface. For example, a body can be constructed by extruding a contour on a curved surface obtained from a loop of one of the faces of a solid body shown in Fig. 13. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.12.png
   :width: 15cm
   :align: center

   Fig. 13

Fig. 14 shows a body obtained by extruding the contour on the curved surface shown in Fig. 13. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.13.png
   :width: 15cm
   :align: center

   Fig. 14

Fig. 15 shows a thin-walled body obtained by extruding the contour on the curved surface shown in Fig. 13. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.14.png
   :width: 15cm
   :align: center

   Fig. 15

Fig. 16 shows an open body obtained by extruding the contour on the curved surface shown in Fig. 13. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.15.png
   :width: 15cm
   :align: center

   Fig. 16

If multiple non-intersecting two-dimensional contours lie on one surface, the considered function determines outer contours and inner contours nested in them, with potentially multiple nesting levels. Fig. 17 shows multiple non-intersecting two-dimensional contours **contours** and a planar surface **surface** (:blue:`MbPlane`). 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.16.png
   :width: 15cm
   :align: center

   Fig. 17

Fig. 18 shows a closed body consisting of several parts constructed by extruding the multiple contours shown in Fig. 17. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.17.png
   :width: 15cm
   :align: center

   Fig. 18

Fig. 19 shows a closed body consisting of several parts constructed by extruding with a draft the multiple contours shown in Fig. 17. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.18.png
   :width: 15cm
   :align: center

   Fig. 19

Fig. 20 shows a closed thin-walled body consisting of several parts constructed by extruding the multiple contours shown in Fig. 17. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.19.png
   :width: 15cm
   :align: center

   Fig. 20

Fig. 21 shows two three-dimensional contours: 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.20.png
   :width: 15cm
   :align: center

   Fig. 21

Fig. 22 shows a doubly connected thin-walled closed body obtained by extruding the three-dimensional contours shown in Fig. 21. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.21.png
   :width: 15cm
   :align: center

   Fig. 22

Fig. 23 shows two open bodies obtained by extruding the three-dimensional contours shown in Fig. 21. The construction is performed separately for each contour. 

.. figure:: /MODELER/METHODS_OF_SOLID_BUILDING/pictures/M.1.3.22.png
   :width: 15cm
   :align: center

   Fig. 23

The extrusion body construction function :blue:`ExtrusionSolid`\() adds the :blue:`MbCurveExtrusionSolid` builder to the history of the constructed body, which contains all the data required for constructing the body. The :blue:`MbCurveExtrusionSolid` builder is declared in the *cr_extrusion_solid.h* file. 

In the *test.exe* application, extrusion body construction is performed by the “Create->Body->Based on curves->By surface curve extrusion” and “Create->Body->Based on curves->By three-dimensional curve extrusion” menu commands.