Generic Fixings Representing Joints and Fittings

A Fixing can represent any type of joint or fitting attached to a Generic Section. It can own other Fixings, so that it can also represent compound joints and fittings. Its geometry is defined by a reference to a parameterized Catalog item in the usual way.

The position and orientation of a Fixing attached (indirectly) to a GENSEC are specified by reference to the coordinate systems of the parent PLDATUM and JLDATUM. These can be set relative to any POINSP under the GENSEC, including a POINSP which has been specially inserted for this purpose if necessary, as summarized in Positioning Items Relative to Generic Sections. The default position and orientation of the Fixing relative to its owning PLDATUM are specified by its POS and ORI attributes, respectively.

Fixings Representing Joints

The detailed position of a Fixing whose SPREF attribute points to a Catalog Joint is specified using the Joining Line attributes of the owning and attached sections: JLNS (start) and JLNE (end). The JNLS/JNLE are related to the origin and orientation of the joint; if the attached GENSEC is curved, these p-lines are taken as parallel to the attached end of the GENSEC. When connected, the JLNS/JLNE line of the attached section intersects with the JLIN line of the Fixing on the Joint Origin Plane.

A GENSEC attached to a joint at one end will have either its JOIS (start) or JOIE (end) attribute set to reference the Fixing; conversely, the CREF (Connection Reference) attribute of the Fixing will reference the attached GENSEC. This two-way cross-reference is used when either the Fixing or the GENSEC is modified, or when a CONNECT command is used.