The Layers thickness type is suitable for models whose surfaces have a multilayer structure. They are used mainly in timber structures (cross-laminated timber) and glass structures (composite and insulating glass). You can then define the layer structure row by row in the "Layers" tab.
Im Kapitel Eingabe des Mehrschichtige Flächen-Handbuchs ist beschrieben, wie Sie die Schichten einer Dicke definieren.