In contrast to a normal cable member, the displacement is possible only in the internal nodes in longitudinal direction ux. Therefore, the member may not be subjected to member loads that act in the local y- or z‑direction. At the internal nodes of the polyline, it is not important whether there is a nodal support or the member is connected to another structure: Because the global system of the cable member is analyzed over the length of the polyline.
The image shows a simple example for this member type. This is a simple pulley block with a loose sheave.