==============================
**Node chains (Knotenketten)**
==============================

.. role:: red
	  
.. admonition:: Command: ndt(*dist*)

 Sets the reference node-spacing. If nc_line or nc_circle specifies the number of nodes as 0, the number of nodes will be determined by the reference node spacing.

 **Parameter**
  :red:`dist` Distance in global units

.. admonition:: Command: nc_line(*x1, y1, x2, y2, nodes*)
		
 Create a node-chain  
 
 **Parameter**
  | :red:`x1,y1` Start-node coordinates
  | :red:`x2,y2` End-node coordinates
  | :red:`nodes` No. of nodes

.. admonition:: Command: nc_line_cont(*x, y, nodes*)

 Continue a node-chain
 
 **Parameter**
  | :red:`x,y` End-node coordinates 
  | :red:`nodes` No. of nodes

.. admonition:: Function: *nodesgen* = nc.circle(*x1, y1, x2, y2, nodes*)

 Create a node-chain on a circular segment defined by the points p1=(x1,y1) and p2=(x2,y2) defined in Cartesian coordinates.  The circular segment is created starting at p1 in a mathematically positive direction around the origin of the reference system.  A full circle is created if p1 = p2,  or if p2 is not specified as an argument. If nodes=0, the number of nodes is set according to the reference node-spacing; (see ndt command).

 **Parameter**
  | :red:`x1,y1` Start-point coordinates 
  | :red:`x2,y2` End-point coordinates (following the mathematically positive direction) 
  | :red:`nodes` No. of nodes 

 **Return value**
  :red:`nodesgen` Number of nodes created (in case nodes = 0)

 **Examples:**

 Arc between points p1=(x1,y1) and p2=(x2,y2) with 20 nodes
 ::
    
  nc_circle(x1,y1,x2,y2,20) 

 Arc between points p1=(x1,y1) and p2=(x2,y2) with the node spacing defined by *ndt*. The number of nodes generated is returned in N.
 ::

  N = nc_circle(x1,y1,x2,y2,0)

 Full circle with 100 nodes
 ::
    
  nc_circle(x1,y1,100)
 
.. admonition:: Function: *nodesgen* = nc_circle_m(*x1, y1, x2, y2, xm, ym, rm, nodes*)

 Create a node-chain on a circular segment defined by the points p1=(x1,y1) and p2=(x2,y2) around the centre pm=(xm,ym) defined in Cartesian coordinates with a radius rm. Some arguments are optional. The circular segment is created starting at p1 in a mathematically positive direction around the centre. A full circle is created if p1 = p2, or if p2 is not specified as an argument. If nodes=0, the number of nodes is set according to the reference node-spacing; (see `ndt` command).
  
 **Parameter**
  | :red:`x1,y1` Start-point coordinates 
  | :red:`x2,y2` End-point coordinates (following the mathematically positivedirection)
  | :red:`xm,ym` Middle-point 
  | :red:`rm` Radius 
  | :red:`nodes` No. of nodes

 **Rückgabewerte**
  :red:`nodesgen` Number of nodes created (in case nodes = 0)


 **Beispiele:** 

 Arc between points p1=(x1,y1) and p2=(x2,y2) with 20 nodes
 ::
 
  nc_circle_m(x1,y1,x2,y2,xm,ym,20)

 Arc between points p1=(x1,y1) and p2=(x2,y2) with the node spacing defined by ndt. The number of nodes generated is returned in N.
 ::
    
  N = nc_circle_m(x1,y1,x2,y2,xm,ym,0)

 Full circle with 100 nodes around the center pm=(xm,ym) starting with the point p1=(x1,y1).
 ::
    
  nc_circle_m(x1,y1,xm,ym,100)


 Full circle with 100 nodes around the center pm=(xm,ym) starting with the point p1=(x1,y1)with the radius r.
 ::
    
  nc_circle_m(xm,ym,r,100)
 
.. admonition:: Command: mirror_nodechains(*x1, y1, x2, y2*)

 Mirroring nodechain structures including mesh. The points of the mirror axis are given in counter-clockwise direction to the corners of the area to be mirrored.

 .. image:: mirror.png

 Point 1 is the lower right corner and point 2 the upper right corner of the area in the example.
 If it should be mirrored on the left edge, then point 1 is the upper left corner and point 2 the lower left.
 Only the starting and end point of the node chains have to be on the mirroring axis.

 **Parameter**
  | :red:`x1,y1` Point 1 
  | :red:`x1,y2` Point 2 of the mirroring axis 
   
.. admonition:: Command: rotate_copy_nodechains(*x1, y1, x2, y2, x3, y3, x4, y4, count*)

 Rotating and copying of the node chain structure including the mesh.
 The points 1 to 4 are to be given in counter clockwise direction to the area to be copied.
 Point 1 and 2 define the edge segment to be copied and points 3 and 4 define the borderline to be expanded.

 .. image:: rotate-copy.png
  
 **Parameter**
  | :red:`x1,y1` Point 1 
  | :red:`x2,y2` Point 2 
  | :red:`x3,y3` Point 3 
  | :red:`x4,y4` Point 4 
  | :red:`count` No. of copies

.. admonition:: Command: translate_copy_nodechains(*x1, y1, x2, y2, x3, y3, x4, y4, count*)

 Moving and copying of the node chain stuctures including the mesh. 
 The points 1 to 4 are to be given in counter clockwise direction to the area to be copied.
 Die Punkte 1 bis 4 sind bezüglich der Ecken des zu vervielfältigenden Gebietes entgegen dem Uhrzeigersinn anzugeben. Point 1 and 2 define the edge segment to be copied and points 3 and 4 define the borderline to be expanded.
 
 **Parameter**
  | :red:`x1,y1` Point 1 
  | :red:`x2,y2` Point 2 
  | :red:`x3,y3` Point 3 
  | :red:`x4,y4` Point 4 
  | :red:`count` No. of copies

.. admonition:: Command: del_nc_single(*x1, y1*)

 Deleting of a node chain including its superelements.
  
 **Parameter**
  :red:`x1,y1` Point near the node chain to be deleted.