Geometry-based modeling and simulation of construction processes

This research describes a new approach for modeling and simulation of construction processes based on geometric models and techniques. Currently, there is inadequate support for modeling the spatial aspects of construction operations, evaluation of alternative process plans and visualizing the results directly. Extending existing planning, simulation, and visualization techniques and using geometry, I describe a process modeling approach and geometric techniques to support the approach. GPM, the process modeling approach in this research, models the conversions in construction processes as sequences of crews acting on geometric work locations. It uses a simple process description: work locations are processed by crews. It describes a crew model that includes a workflow strategy and a production rate function. The workflow strategy specifies in what order crews plan to perform their scope of work. The production rate function specifies at what rate crews can perform work at a specific work location at a specific time instant. A set of crews acting on work locations in a bounded space defines a subsystem. Subsystems use formal approaches to modeling and simulation for their definition. GPM describes three interaction types to couple a set of subsystems to describe the complete process model. It reduces each subsystem into queueing networks for simulation purposes and uses discrete event simulation to obtain state trajectories for the geometric model and the crews performing work on the project. The system states provide automatic 4D and crew performance visualizations. In this research, geometry is not a static representational element, but an integral part of the process model. The geometric model, represented as triangle meshes, is a source for automated extraction of a number of constraints and interactions. The geometric techniques manipulate, reorganize and analyze the geometric model. GSim, an implementation prototype for GPM, implements the elements of the modeling and simulation approach and the geometric techniques. Users can define subsystems interactively and evaluate alternatives easily by changing parameters and observing the results directly. The research results provide improved modeling and simulation techniques for construction operations and more effective use of geometry for practice and research.