# Make Symmetry¶

There are three differents ways to make the symmetry of an element:

• Symmetry by point
• Symmetry by line
• Symmetry by plane

## Symmetry by point¶

To make the symmetry of an element by point, you need to define:

• the element
• the symmetry center
`elts = doc.makeSymmetryPoint (grid, orig)`

Operations on elts: Elements

Here is an example where we make the symmetry of a grid:

### Example¶

```# -*- coding: latin-1 -*-
# Copyright (C) 2009-2016  CEA/DEN, EDF R&D
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
#
# See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
#

######## Make Symmetry Point ########

import hexablock

# ======================================================= make_grid
def make_grid (doc) :

ori  = doc.addVertex ( 0, 0, 0)
vz   = doc.addVector ( 0, 0, 1)
vx   = doc.addVector ( 1 ,0, 0)

dr = 1
da = 360
dl = 1

nr = 1
na = 6
nl = 1
grid = doc.makeCylindrical (ori, vx,vz, dr,da,dl, nr,na,nl, False)
#####  doc .saveVtk ("cyl_grid.vtk")
return grid

# ======================================================= test_sym_point
def test_sym_point () :

grid = make_grid (doc)

orig = grid.getVertex(3)
grid2 = doc.makeSymmetryPoint (grid, orig)

#####  doc .saveVtk ("sym_point.vtk")
return doc

# ================================================================= Begin
doc = test_sym_point  ()

```

### Result¶

Initial

Symmetry of a grid by point

## Symmetry by line¶

To make the symmetry of an element by line, you need to define:

• the element
• a point and a direction to define the line of symmetry
`elts = doc.makeSymmetryLine (grid, orig, dir)`

Operations on elts: Elements

### Code¶

```# -*- coding: latin-1 -*-
# Copyright (C) 2009-2016  CEA/DEN, EDF R&D
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
#
# See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
#

######## Make Symmetry Line ########

import hexablock

# ======================================================= make_grid
def make_grid (doc) :

ori  = doc.addVertex ( 0, 0, 0)
vz   = doc.addVector ( 0, 0, 1)
vx   = doc.addVector ( 1 ,0, 0)

dr = 1
da = 360
dl = 1

nr = 1
na = 6
nl = 1
grid = doc.makeCylindrical (ori, vx,vz, dr,da,dl, nr,na,nl, False)
#####  doc .saveVtk ("cyl_grid.vtk")
return grid

# ======================================================= test_sym_line
def test_sym_line () :

grid = make_grid (doc)

orig = grid.getVertex(3)
dir   = doc.addVector (0, 0, 1);
grid2 = doc.makeSymmetryLine (grid, orig, dir)

#####  doc .saveVtk ("sym_line.vtk")
return doc

# ================================================================= Begin
doc = test_sym_line  ()
```

### Result¶

Symmetry of a grid by line

## Symmetry by plane¶

To make the symmetry of an element by plane, you need to define:

• the element
• a point and a direction to define the plane of symmetry
`elts = doc.makeSymmetryPlane (grid, orig, dir)`

Operations on elts: Elements

### Code¶

```# -*- coding: latin-1 -*-
# Copyright (C) 2009-2016  CEA/DEN, EDF R&D
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
#
# See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
#

######## Make Symmetry Plane ########

import hexablock

# ======================================================= make_grid
def make_grid (doc) :

ori  = doc.addVertex ( 0, 0, 0)
vz   = doc.addVector ( 0, 0, 1)
vx   = doc.addVector ( 1 ,0, 0)

dr = 1
da = 360
dl = 1

nr = 1
na = 6
nl = 1
grid = doc.makeCylindrical (ori, vx,vz, dr,da,dl, nr,na,nl, False)
#####  doc .saveVtk ("cyl_grid.vtk")
return grid

# ======================================================= test_sym_plane
def test_sym_plane () :

grid = make_grid (doc)

orig = grid.getVertex(3)
dir   = doc.addVector (0, 1, 0);
grid2 = doc.makeSymmetryPlane (grid, orig, dir)

#####  doc .saveVtk ("sym_plane.vtk")
return doc

# ================================================================= Begin
doc = test_sym_plane  ()
```

### Result¶

Symmetry of a grid by plane

GUI command: Make elements by symmetry