This is the stage where the architect's initial ideas become a detailed plan. If the project requires a structural or facility engineer, those people usually join the team at this stage. The architect also provides the client with renderings of the exterior and interior spaces that are being finalized. The output of this phase greatly affects the total cost of a construction project (as well as the project schedule). Therefore, it should be done with utmost care. At the end of this stage, a more realistic estimate of the building costs is obtained.