This thesis addresses issues related to the development of Collaborative Virtual Environments (CVEs) for architectural design use. Today a new level of complexity has been brought to the meaning of virtuality by the creation of network-based virtual communities and the use of avatars along with multimedia which provides the technology for remote presence and collaborative experience. Communication and especially collaboration among design teams are now key factors in making the design process faster and more efficient in order to achieve increased competitiveness in the construction market. The objective of this thesis is to present a tool that is capable of creating 3D shapes in a shared VR environment, therefore allowing the evolution of the design to be a shared process. Along with its companion thesis (Conti, 2002) it gives the description of a framework and software prototype which could help practitioners using Virtual Reality technology by being a new interface for collaborative design at the early stages of the design process. The prototype system that is described here is called Java™ Collaborative Architectural Design tool in Virtual Reality JCAD-VR) and this thesis presents a description of its collaborative architecture. This thesis gives a description of the phases and technical solutions in the development of the network architecture and collaborative features of the JCAD-VR system. In addition, several different communication tools were used to enhance communication and the flow of information among the design teams and they are integrated in a Virtual Environment specifically created for architects. After the description of the software development the results are given of a test of the collaborative architecture of JCAD-VR and its ease of use in a real multi participant design experiment which show the potential and efficiency of using CVEs in architecture.