The most important role of Quantity Surveyors is to estimate the cost of the proposed building; enabling the contractor to evaluate and determine the feasibility of the project. Hence accuracy of forecasting the cost of future projects is vital to the success of the business or organization involving in future construction projects.
A Professional Quantity Surveyor has a comprehensive knowledge of construction, construction methods, local laws relating to construction projects and accounting, in order to provide cost and financial advice.
The foundation for a successful cost estimate relies upon reliable identification of the quantities (takeoff) of the various materials involved in the project. Cost estimators develop the cost information based on the design developed by the design team members which will help the team to make budgetary and feasibility determinations.
A purpose-built BIM solution like Revit features computable building information that enables a model to be understood by a computer as a building. A wall for example, "knows" what it is and how to react to the rest of the building. As such, it can be scheduled or quantified as a wall: a building assembly made of real materials. Computable building information supports numerous building design and construction activities: structural analysis, MEP system modeling, building energy analysis, and specification management, to name just a few.
Cost estimating is yet another aspect of the building process that can benefit from computable building information. Designing a building is the responsibility of architects, whereas assessing the cost to build it is the domain of estimators. In general, the architect's scope of work doesn't extend to material takeoffs or cost information. That's left to the estimator.