AEC 4D Production Model: Definition and Automated Generation

To manage a construction project, project managers need a model of the construction process that answers the question: who is doing what when and where. We refer to such an integrated and computer-interpretable model as a 4D production model. This model links objects representing project components (C), actions (A), resources (R), and sequencing constraints (S) to activities. It needs to exist at multiple levels of detail, appropriate for owners, general contractors, sub-contractors, and crews. Despite computer-based design and project management tools, today's practitioners cannot rapidly and seamlessly synthesize 4D production models at these levels of detail from a project description modeled in a 3D CAD system. This paper presents a hierarchical construction method-driven planning mechanism and introduces the Construction Method Modeler (CMM) planning system based on the mechanism. Planning knowledge captured in user-defined and selected method models allows CMM to generate 4D production models rapidly at the desired level of detail. The content of a construction method model specifies why activities in a 4D production model exist and are linked to particular entities. Formalized activity generation and sequencing knowledge instructs method models how to generate activities and sequence them. To maintain a representation of activities at every level of detail in the 4D production model, CMM invokes product model transformation mechanisms. These transformation mechanisms automatically translate a design version of the project description into a production version. The main contributions of the paper lie in the definition of a 4D production model, the formalization of the hierarchical method-driven planning process, and descriptions of how we operationalized three product model transformation mechanisms.