<![CDATA[Conventional building planning based on two-dimensional drawings may create challenges in coordinating building elements, calculating material quantities, and preparing reliable cost estimates. This study examines the application of Building Information Modeling (BIM) to integrate design coordination, quantity take-off, construction scheduling, and cost estimation in the planning of a three-story Contractor Office Building in Serang City, Indonesia, with a total floor area of 450 m². A comparative approach was employed by developing a Level of Development (LOD) 300 model using Autodesk Revit 2023 and comparing its quantity and cost outputs with conventional planning documents. The analysis also involved clash detection and construction scheduling using Microsoft Project. The initial interference check identified 31 clashes between structural columns and tie beams. Following geometric adjustments and resolution procedures, the recheck detected no remaining interference within the tested elements and checking rules. The quantity take-off comparison showed deviations of 1.73% for reinforcement, 6.96% for formwork, and 12.58% for concrete, with conventional calculations producing higher quantities in all three categories. The resulting construction schedule indicated a planned duration of 83 working days. Furthermore, the BIM-based cost estimate amounted to IDR 1,382,971,143, compared with IDR 1,419,871,282 using conventional calculations, representing a difference of IDR 36,900,139 or 2.60%. These findings demonstrate the potential of BIM to connect geometric modeling, design coordination, quantity extraction, scheduling, and cost estimation within an integrated planning process. Nevertheless, the cost difference represents a comparison of planning estimates rather than verified savings during actual construction.]]>
