# Interpolation of Cross Sections¶

The interpolation of cross sections takes place automatically during the export from SOFiPLUS(-X). Beside from the definition of the cross section, a requirement for the interpolation includes the definition of a minimum of one beam or structural line with different start and end cross sections (type 1). For type 2 the definition of a master cross section is required with appropriate references and variables, which have to be defined at an axis.

Interpolated cross sections are created for all beam sections and intermediate nodes. These are not editable in the Cross Section Editor (see Cooperation with the other SOFiSTiK Modules).

There are two different types for interpolation of cross sections:

**1.** Linear interpolation between two cross sections whose construction is identical.

To avoid interpolation problems, it is recommended to generate the second cross section by a copy of the first one for the method of the linear interpolation. A copy can be made by right clicking on the cross section in the Sidebar and selecting the option Clone. The geometry of the copied cross section can then be modified, however, it is still suitable for interpolation because it is of identical construction to the first.

**2.** Interpolation of the cross section geometry using reference points and variables along the axis.

This option is available only for customers with a CABD license. For the interpolation along an axis, only a master cross section is required. Variable points (reference points) are defined in this section and can be assigned to corresponding variables/axes. In the case of an interpolation with a master cross section, the numbers of the interpolated cross sections can be influenced as follows:

The master cross section has to be numbered 100 or greater.

The interpolated cross sections start then with the number of the master cross section + 1.

E.g. if the master cross section receives the number 200, then the interpolated cross sections start with number 201.

Note

Only coordinates and dimensions can be interpolated. A linear interpolation of variables is not possible. Variables have to be defined at the axes and the interpolation has to be occured according to the second variant with a master cross section.