# A.2.6: Approach Used for Cross Section Optimization

Karamba3D does cross section design by going through the list of cross sections in a group of cross sections called a family. It starts at the first entry and proceeds to the next until a cross section is found that is sufficient for the given cross section forces of an element.

The calculation of the utilization of a beam is done using the procedure described in EN 1993-1-1 i.e. Eurocode (EC) 3 [\[5\]](https://manual.karamba3d.com/appendix/bibliography). It takes account of buckling and lateral torsional buckling. The superposition of different cross section forces works according to procedure 2 (see annex B of EC 3). The values $$C\_{my}$$, $$C\_{mz}$$and $$C\_{mLT}$$are limited to 0.9. The **“Utilization”**-component’s **“Details”**-output returns a listing of intermediate values from the calculation according to EC3 (see section [3.6.6](https://manual.karamba3d.com/3-in-depth-component-reference/3.6-results/3.7.1-general-results/3.6.6-utilization-of-elements)). For a detailed comparison of the steel design procedures implemented in Karamba3D and Dlubal's RFEM see [\[9\]](https://manual.karamba3d.com/appendix/bibliography).