An object-oriented design intent externalization and representation model for cost estimating applications

Abstract

The multidisciplinary nature of the Architecture-Engineering-Construction industry, the involvement of parties with different professional backgrounds and the use of incompatible software at different phases of project development result in fragile communication between design and construction. The software used at different phases of project development represents and manipulates product knowledge rather than process knowledge, so do the design drawings and specifications. The process knowledge that remains trapped in the design phase can however be used in interpreting the meaning about the form represented on design drawings. A better understanding of process knowledge can restructure and enhance construction related processes and strengthen the communication between design and construction.

This research focuses on reconfiguring the flow of information between architectural design and construction by identifying that part of the process knowledge also referred to as "design intent," which is of essence to cost estimating. Design intent can improve various facets of cost estimating. This research discusses the potential use of design intent knowledge in material selection and substitution, shop drawing preparation and value engineering.

The first objective of the research is to define the term design intent, find examples of it and classify it in a format that can be used in construction applications. Thus, design intent has been classified under four classification schemes in this research: (1) Attributive; (2) Relational; (3) Priority; and (4) Implicit/ Explicit. The first two classification schemes have further been structured into its detailed subclasses and the potential use of each type of design intent has been discussed in detail.

The second objective of the research is to represent and reason with design intent to improve cost estimating applications. Thus, the thesis describes an object-oriented design intent representation model implemented in a proof-of-concept prototype called Skull Object Space (SOS). The benefits of using such a representation model is illustrated in a material application module implemented as a small scale computer prototype that makes material selection and substitution for the contractor.

Both SOS and the Material Application Module provide useful framework for future enhancements in externalization and representation of design intent.