Quantity takeoff and cost estimating software that measures directly off a BIM model or 2D drawings to produce a priced Bill of Quantities. A quantity surveyor links CostX directly to the Revit model (or an exported IFC file) so measured quantities update automatically as the design changes, instead of manually re-measuring drawings every time a revision comes through - the same underlying goal as Assemble Systems, from a cost-estimating-first rather than model-coordination-first tool.