CS_DEF

Defines coordinate systems with reference to an existing coordinate system or three nodes.

This page discusses:

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Coordinate Systems (CS_DEF)

ID_NAME

= <name_of_coord_system>

Name of the coordinate system

CS_TYPE

= RECTANGULAR

= CYLINDRICAL

= SPHERICAL

Type of new coordinate system

DEF_TYPE

= LOCAL

LOCAL definition refers to an existing coordinate system

= NODE

Definition using three nodes

= VECTOR

Definition using an origin and three vectors

Items for DEF_TYPE = LOCAL

CS_REF

= <name_of_coord_system>

Existing reference coordinate system

ORIGIN_123

= <coord_1>, <coord_2>, <coord_3>

Coordinate values of the origin

ROTATION_321

= <rot_3>, <rot_2>, <rot_1>

Rotations that should be superimposed on the reference coordinate system

Items for DEF_TYPE = NODE

CS_AXIS

Specifies the axis and the plane defined by the three nodes.

= X_XY

X-axis and the X-Y plane are defined by the three nodes.

= X_XZ

X-axis and X-Z plane are defined by the nodes.

= Z_XZ

Z-axis and X-Z plane are defined by the nodes.

NODE_ORIGIN

= <node_id_of_origin>

ID of node which defines the origin

NODE_AXIS

= <node_id_on_axis>

ID of the node on the axis

NODE_PLANE

= <node_id_on_plane>

ID of the node on the given plane and the second axis

Items for DEF_TYPE = VECTOR

ORIGIN

= <coord_1>, <coord_2>, <coord_3>

Coordinate values of the origin

VECTOR_X

= <coord_1>, <coord_2>, <coord_3>

Direction of the first reference vector.

VECTOR_Y

= <coord_1>, <coord_2>, <coord_3>

Direction of the second reference vector.

VECTOR_Z

= <coord_1>, <coord_2>, <coord_3>

Direction of the third reference vector.

Remark

  • The rotation matrix given by VECTOR_X, VECTOR_Y, VECTOR_Z must have a determinant of 1:

    absdetm=absdetVECTOR_X, VECTOR_Y, VECTOR_Z=1

  • The rotation angles in the command ROTATION_321 are in degrees. The single rotations are carried out in series around the axis of the local Cartesian coordinate. The following figure shows the rotations for ROTATION_321 = 180.0, 0.0, 90.0:

  • The longitudinal axis of a cylindrical coordinate system is defined by the z-axis of the referenced rectangular coordinate system. Respectively, the polar axis equals the x-axis, as shown in the following image:

Examples

The following command defines a cylindrical coordinate system with origin (10,20,0) with respect to the global Cartesian coordinate system CS_0. The polar axis and longitudinal axis are obtained by rotating the x-axis and z-axis of CS_0 respectively by 45° around the z-axis and by 15° around the y-axis of CS_0.


CS_DEF
  ID_NAME      = my_cs_01
  CS_TYPE      = CYLINDRICAL
  DEF_TYPE     = LOCAL
  CS_REF       = cs_0
  ORIGIN_123   = 10.0, 20.0, 30.0
  ROTATION_321 = 45.0, 15.0, 0.0
END_

The following command defines a rectangular (Cartesian) coordinate system with origin through the node with ID number 10. The x-axis is defined by the nodes 10 and 100. Node 101 defines a point in the x-y plane.


CS_DEF
  ID_NAME     = my_cs_02
  CS_TYPE     = RECTANGULAR
  DEF_TYPE    = NODE
  CS_AXIS     = X_XY
  NODE_ORIGIN = 10
  NODE_AXIS   = 100
  NODE_PLANE  = 101
END_

The following command defines a rectangular (Cartesian) coordinate system with origin (10,10,10). The x-axis is defined by the vector (-1,0,0), y-axis with the vector (0,-1,0) and the z-axis with (0,0,-1).


CS_DEF
  ID_NAME  = my_cs
  CS_TYPE  = RECTANGULAR
  DEF_TYPE = VECTOR
  ORIGIN   = 10,10,10
  VECTOR_X = -1,0,0
  VECTOR_Y = 0,-1,0
  VECTOR_Z = 0,0,-1
END_