CivilFEM uses two coordinate systems in beam sections: the CivilFEM axis system (XCF, YCF, ZCF) and the section axes system (XS, YS, ZS).
For the orientation of the cross sections of the shapes in the CivilFEM axis system, the center of gravity of the section coincides with the origin of these axes and the shape of the web is parallel to the CivilFEM Y axis.
Furthermore, the section axis system (XS, YS, ZS) is located on a singular point of the section geometry, parallel to the CivilFEM axis. This system includes the coordinates of the center of gravity, the points of the section, and the coordinates of the plate structure for steel sections. The location of this section axis system is conventional and depends on the type of section considered.
Another coordinate system exists for steel sections and for each particular code where the user can indicate the results they wish to obtain; these results are given in this system. These coordinates systems do not have to coincide with the ones listed above, and their location is shown in the corresponding sections of this Manual.
The following graphics show the location and the orientation, for the different sections, of both the CivilFEM axis system and the section axis system, denominated as follows:
