Straight Sections

Each individual straight structural member (column, beam and so on) is represented in PDMS by a Section (SCTN) element. The geometry of a Section is defined by two types of attribute setting:

• Its cross-section is defined by reference to a Catalogue Profile (SPRF) element (I‑beam, T-section, Channel, and so on).

• All other aspects of its geometry are defined by setting specific design attributes (in most cases these are set automatically by PDMS as the model is manipulated graphically). Two of the most important attributes are the Start Position (POSS) and the End Position (POSE), since the positions of these points effectively determine the length and orientation of the item. These and some other attributes of Sections will be looked at in more detail later.

To provide a method for referring to individual edges and faces of a Section, each is identified by a named line which runs along the length of the Section. These reference lines (which are derived from the Section’s Profile definition in the catalogue) are called P-lines. As an example, some of the most commonly used p-lines for an I-shaped Profile might be positioned and named as follows:

Note: for further information on this and other profiles, refer to Structural Catalog Guide.