As of the 2021.b version, the properties of an IFC entity (IfcPropertySet) can be used in the "Set of measurement rules" of the project to generate the quantity take-off (variables B, C and D), as was already done previously with the quantities (IfcQuantitySet). The reason for this implementation is due to the existence of BIM modellers that are based on the IFC standard, which export quantity-orientated attribute groups as properties (IfcPorpertySet), instead of quantities (IfcQuantitySet). Now, in the job or project units panel of a "Measurement rule", users must indicate the type of attribute that is to be assigned to each variable, similar to what must be done when selecting the entities of the BIM model.
