A Framework for Augmenting 4D Visualization of Construction Projects with Scheduling Uncertainties

Along with the advent of Building Information Modeling (BIM) came the rising popularity of visualizing not only the product of a project but also the underlying activities leading to such products. For this purpose, the schedule of a project is coupled with its 3D model to visualize how different components of a project are placed during the construction, creating what is known as a 4D model. Through enabling a detailed visualization of the construction processes, 4D models allow the scrutiny of a chosen construction method or schedule for the feasibility in view of the space required for the execution of different tasks. Nevertheless, while there exist several methods to generate a stochastic schedule of a construction project, the de facto practice in the generation and application of 4D models is based on the application of deterministic schedules. Accordingly, the current 4D models cannot represent the uncertainties associated with the start and end time of various construction activities. As a result, any decisions made about the constructability of a project on account of the existing 4D models ignores the risks of delays in the completion of activities and the ensued potential constructability conflicts. This research aims to develop a framework to effectively visualize the risk of constructability conflicts associated with the construction projects. In other words, using the stochastic scheduling paradigm, the proposed framework enables augmenting the existing 4D models with information about the probability of each elements being under construction at any given time. A case study is developed to integrate the stochastic schedules coming from the discrete-event simulation tool with the 3D model of the building and further visualize the scheduling uncertainty in the 4D visualization. It is shown that the proposed method has a strong potential to provide inputs for more precise constructability analysis.