Setting out a building is the process of transferring architectural proposals from drawings into the ground. It establishes the location points for site boundaries, foundations, columns, centre-lines of walls and other necessary structural parts. Also, it establishes the buiding's correct extent, angle and level. The whole structure will be located and erected according to the initial setting out. Accurate setting out is therefore a fundamental part of the construction works, and errors can be very expensive and time consuming to correct. It should only be undertaken by competent persons, and all work should be thoroughly checked, preferably by different personnel. Setting out is usually undertaken once the site has been subject to a condition survey and desk study, and has been cleared of any debris, unwanted vegetation or obstructions. Works necessary to create required levels may also have been completed before the layout process begins.