The successful implementation of complex-shaped buildings within feasible time and budget limits, has brought attention to the potential of computer-aided design and manufacturing technologies (CAD/CAM), Building Information Modeling (BIM), and the need for integrated practice. At the core of an integrated practice vision lies the intimate collaboration between the design team and construction team and a digital three-dimensional model, often with parametric and intelligent characteristics. With the shift from two-dimensional (2D) paper-based representations to threedimensional (3D) geometric representations in building information models (BIM), architects and engineers have streamlined 'inner' design team communication and collaboration. However, practice conventions have posed significant challenges when attempting to collaborate on the designer's 3D model with the 'external' design team-involving the architect (or engineer)-of-record, and contractor, construction manager or fabricator, etc. Focusing on the execution of complex-shaped buildings, the objective of this paper is to illustrate varying collaborative approaches to understand how design teams use 3D models to control geometry. The authors attempt to provide specific responses to the following questions: What are the issues when collaborating on 3D models? What are the mechanisms that design teams adopt to surpass practice conventions? The findings from three case studies suggest that collaboration methodologies on 3D models differ with the architects' approaches to geometry control. The authors will demonstrate that successful model-based collaboration occurs either on a contractual or non-contractual model issued by the architect.