Hello! I suggest that you first analyze the plans and adapt them using good modeling practices. If it is confined, it should also be modeled confined to avoid leaks. The objective is to have a physical twin. The tools allow you to go into detail using them appropriately. As for the density and physical and radioelectric properties, they are specified in the properties of each component material. They can also be customized if you have the data. The criteria when selecting materials are important. The main thing is to look for similarity in terms of radioelectric properties. In the case presented, concrete (structural) is much denser than a plasterboard (Durlock), and they also have a significant difference in thickness. The properties show the same. In the image above of the doors, the walls must be closed, otherwise there will be erroneous predictions. I hope it is useful. Greetings!