So far, the use of Building Information Modeling (BIM) to support automatic prefabrication and onsite assembly processes during a construction project has been limited. The modeling and management of information concerning the diverse elements involved in these construction processes, such as activities, objects, flows and operations, has not been sufficiently studied. In order to support the proper handling of construction process information and improve productivity, a process information modeling framework is developed in the present research. This paper presents an ontology model for supporting information handling of off-site automatic prefabrication and on-site assembly, which can incorporate manifold aspects (e.g. geometry, functionality, physicality) of building production subsystems. The object-oriented framework can support the semi-automatic preparation of digital information for off-site component prefabrication, and the simulation of the production process while considering variables such as the geometry of building components, material attributes and production speed. The framework can also support the definition of a project specific assembly activity and the simulation of on-site assembly activities such as component unloading, mounting, hoisting and positioning, while considering construction engineering constraints such as the lifting capacity and speed of cranes. As a result, the 3D model of the building component is updated to reflect its actual motion on the site during assembly processes.