Code identifying geometric space of the model,
-2 = Axisymmetric RZ,
2 = 2-D XY,
3 = 3-D XYZ;

Number of nodes in this model (before symmetry operations);

Number of enclosures in this model (before symmetry operations);

Maximum node ID referenced in the model (before symmetry operations).

Number of symmetry objects defining symmetry operations for this model. The present maximum allowed value is 4.

Immediately following and with no interspersed comments is the symmetry object numeric data, which is read by:

READ( LU,'( 3 (E20.10) )',IOSTAT = IOS, END = 1, ERR = 1 ),
 $   ( ( ( SYMOBJ( K, J, I ), K = 1, 3 ), J = 1, 5 ), I = 1, #SymObj 

The contents of SYMOBJ( 1:3, 1:5, I ) are:

This is repeated #SymObj times.

The symmetry operations are performed in order of increasing index I.

Depending on the value of Type, the data for each symmetry object has different meanings.

For IFIX( Type ) = 1 this is a reflection in 2-D XY or RZ space about a line. The line is defined by two distinct points, (X1,Y1) and (X2,Y2), on the line All other subarray elements should be set to 0.0.

For IFIX( Type ) = 2 this is a reflection in 3-D XYZ space about a plane defined by three distinct points, (X1,Y1,Z1), (X2,Y2,Z2), and (X3,Y3,Z3), all on the plane and not colinear. All other subarray elements should be set to 0.0.

For IFIX( Type ) = 3, this is a rotation about an axis and is valid in 2-D XY and 3-D XYZ spaces. The positive axis of rotation by the right-hand rule is the vector from (X1,Y1,Z1) to (X2,Y2,Z2) and should have nonzero length. For 2-D XY space, this axis must be perpendicular to the XY-plane. The model will be replicated #Rot times by successively rotating #Rot times the model existing before any of these rotations (but including that created by previous symmetry operations) Rot_Angle degrees about the axis of rotation. All other subarray elements should be set to 0.0.

All other values of IFIX(Type) result in a fatal error in P/VF. Only certain combinations of symmetry object types are valid. The valid combinations depend on the model space, as identified by DimCode. In general, symmetry object validity is not checked by P/VF.

For 2-D RZ space (DimCode = -2), the only valid symmetry object is Type = 1 (line) and this line must be perpendicular to the Z-axis. Only one such symmetry object is permitted in 2-D RZ space.

For 2-D XY space (DimCode = 2), only types 1 (line) and 3 (rotation) are valid. Not more than one type 3 object is permitted. Not more than two type 1 objects are permitted. Type 1 objects should be in the XY-plane. Type 3 objects should be perpendicular to the XY-plane. If there are two type 1 objects, they should be mutually perpendicular.

For 3-D XYZ space (DimCode = 3), only symmetry object types 2 (plane) and 3 (rotation) are valid. Not more than one type 3 object is permitted. Not more than three type 2 objects are permitted. Two or more type 2 objects must be mutually perpendicular.

Comments may follow the symmetry object data, but may not occur between the $SYM: keyword line and the end of the symmetry object numeric data.

The next required keyword line is $ENDSYM:. This line contains no other data. If there are no symmetry objects, the $SymObj is zero and the required data is:

 

The ID number of this enclosure.

Number of surfaces in this enclosure.

Maximum number of surface attributes supported = 14;

Array of surface attributes whose elements are:

Real data associated with the surface (presently none is required);
followed by
( 8 ( I10 ) ), ( SurNod( J ), J = 1, SurAtt( 5 ) )

List of node IDs associated with the surface and in the order specified for the corresponding Patran elements.