Evaluating CAD Complexity

When a designer estimates the complexity of a proposed CAD modelling project, two conceptions of complexity may be considered. The first, design complexity, based on visible features of the object to be modelled, is relatively easy to assess before commencement, but is not very reliable. The second, CAD complexity, based on the actual CAD embodiment of the design, is potentially more revealing, but difficult to assess in advance without a clear understanding of what is entailed. Clearer articulation of this under utilised concept is proposed for use in both industrial and educational settings.

We describe here a project currently underway to develop, test and evaluate a formal model of CAD complexity. It is proposed that development of such a model will contribute to better understanding of the organisation of CAD models and facilitate the planning and management of CAD projects. This could lead to a more strategic use of CAD in practice, and potential savings in costs and time.

The presentation consists of the following parts:

• Introductory section describing the significance of this work
• Review of theoretical bases of the concepts of complexity and how they may be applied to CAD
• Description of the project currently underway to develop and test a formal model of CAD complexity

• Production of a CAD model is partially analogous to designing,to the extent that principles associated with good design, such as "morewith less," are also appropriate to development of design models.
• The proposed method of description has applications in both industryand education.
• CAD complexity is becoming an important area of interest, asthe power and use of CAD evolves beyond the "throw away" environments ofdesign, construction and manufacturing, towards long term applicationssuch as system simulations and facility management.