You can activate or deactivate the use of the special solution add-on in the Add-ons tab of the "Model Base Data".
A green dot in front of the add-on description means that a license is available. An orange or blue dot indicates that you can only use the add-on as a demo or trial version with a limited range of functions.
After activating the Building Model add-on, the user interface of RFEM is extended by some new entries in the navigator, tables, and dialog boxes. Thus, the add-on is fully integrated into the RFEM program.