So, here are some note needed to know about how quantities are calculated.

NET VOLUME AND GROSS VOLUME
The difference between gross volume and net volume is that the gross volume is calculated
without the related IFC opening.
So, if an object is created lets say with a hole but without defining the opening, the hole is counted into net volume (so get volume and net volume are the same).
This is in order to follow the native IFC approach.

WALLS 
Walls quantities are calculated with the convention that the object main axis is the 'x'. 
Also openings inside a wall have to main axis 'x'

SLAB THICKNESS
The slab thickness is defined as Width, following the IFC definition
Also, note that these dimensions are calculated only if the slab is prismatic.

LATERAL AREA
All lateral areas are counted, so for example also the inside surfaces.
It shouldn't be like that so we should find a method to only external lateral area.

DOORS AND WINDOWS
Doors and Windows have to have the main axis along 'x' and the height is measured along 'z' axis




