Point Symmetry (POINT_SYM)

Couple displacements that are symmetric with respect to a point.

See Also
In Other Guides
LINK_SHAPE

CLIENT / Applicable for SHAPE_CONTROLLER SHAPE_SENSITIVITY
POINT_SYM OK -

To be able to couple displacements symmetric to a point, the position of the point must be exactly specified. It is also necessary to specify tolerances to identify nodes that lie symmetric to one another relative to the point. The following three parameters are required for the definition of the link condition: 


CLIENT = POINT_SYM
CS     = name_of_coord_system
TOL    = <tol_1>, <tol_2>, <tol_3>

The origin of the coordinate system referenced by CS defines the symmetry point. The symmetry of the nodes (assigned by ND_GROUP in the DVCON_SHAPE command) is checked against the symmetry point. Symmetric nodes are assembled into a symmetry group (normally two symmetric nodes per symmetry group). Then the main node of the symmetry group is determined and the displacements of the client nodes are calculated in such a way that they move symmetric to the point of the main node (see the following figure).

The tolerances are required to identify symmetric nodes. Point symmetric nodes share inversely equal coordinates (and added tolerances). The three tolerance values tol_* are assigned to the three coordinate directions of the coordinate system referenced by CS.

Important:

  • The coordinate system referenced by CS must be a Cartesian coordinate system.
  • Only the MAIN=MAX or MAIN=MIN criteria are allowed for determination of the main node.