Quantity takeoff from 2D and 3D models
‘Taking off’ is a process that involves determining quantities from project models, drawings and specifications, primarily for the purpose of understanding construction costs. Used as a noun, ‘takeoff’ can also refer to the actual quantity lists generated by the process. It facilitates the development of detailed and accurate cost estimates from early project stages, provided a degree of design and specification information is made available.
This section presents an overview of quantity takeoff, defining and discussing terminology before looking at how takeoff data is used. The standards and guidance that govern measurement are then outlined, identifying synergies with RICS NRM1 and 2, and RICS property measurement, 2nd edition.
It then turns to affordances of 2D and 3D design information, touching on the principles and processes of BIM Level 2. The importance of accuracy and implementing checks and balances is also stressed.