This document provides an overview of Building Information Modeling (BIM) and its dimensions. It discusses 3D, 4D, 5D, 6D, and 7D BIM. 3D BIM refers to the visual or geometric component of the model. 4D BIM adds time as a dimension by linking the 3D model to a construction schedule. 5D BIM incorporates cost information. The document describes the benefits and challenges of BIM as well as software used for 4D modeling.