Solids or volumes can be defined as Spaces. Spaces are a fundamental organising tool as it defines rooms that provides a containment structuring tool. See also IFC.

Projects often start with a spatial programme listing the rooms and areas needed. This is also the basis for initial cost estimating and verification for the client.

Bentley Facilities Planner (and Aecosim at one point using the Navigation Pane) can track any element contained within the Space's footprint / volume.

Walls can be associated to the Space's perimeter. It would be good to be able to provide parameteric associative behaviour for the Walls and Slabs (eg ceilings) within the space.

When the Space is flexed, any internal walls would flex accordingly. Typically, the bottom of the Walls would be constrained to the bottom face of the Space, the top of the Wall would be constrained to the top face of the Space and the ends to the side faces, room perimeter.

Some of this is already possible but not persistently linked to the Spaces or other elements for automatic updates.