You can start the [Calculation] in every input window of RF-CONCRETE Surfaces by clicking the corresponding button.
RF-CONCRETE Surfaces searches for the results of the load cases, load combinations, and result combinations to be designed. If they cannot be found, the RFEM calculation for determining the design-relevant internal forces starts first.
You can also start the calculation in the RFEM user interface: The To Calculate dialog box (menu item Calculate → To Calculate) lists the design cases of the add-on modules such as load cases or load combinations.
If the design cases of RF-CONCRETE Surfaces are missing in the Not Calculated list, select All or Add-on Modules in the drop-down list below.
To transfer the selected RF-CONCRETE Surfaces cases to the list on the right, use 
.
Then, click [OK] to start the calculation.
A design case can also be calculated directly by means of the list in the toolbar: Set the RF-CONCRETE Surfaces case and then click the [Show Results] button.
You can subsequently observe the calculation process in a dialog box.