Bulk Data Entry Activates gap direction alignment checking.

Parameter Values Description
YES (Default)
All gap elements of non-zero length (distance between GA-GB) that have a prescribed coordinate system CID are checked for misalignment of gap prescribed axis (x-axis of CID) with the vector GA->GB (angles larger than 30 degrees produce errors). The amount of output is limited to the first ten occurrences. Note that this check applies correctly to the most typical situations where in there is an initial opening between bodies A and B, and the gap element is used to enforce non-penetration condition (for other cases, see the REVERSE option below).
No gap CID direction checks are performed.
Only warnings are issued.
The error or warning messages are printed for all gap elements violating this check.
Orientations of vector GA->GB generally opposite to the prescribed x-axis of CID system are also accepted (this can be used in cases when gap is used to model rope behavior or when there is initial penetration, rather than gap, between bodies A and B). The tolerance levels are the same as for YES, except that they are measured from either 0 or 180 degrees reference angle.

For more details, refer to the CGAP description.

PARAM, CHKGPDIR is superseded by the CKGAPDIR parameter on the GAPPRM Bulk Data Entry, if present.