This paper investigates the role of gaming engines in the architectural design process through the introduction of features such as immersion, interaction and collaboration. While traditional 3D modelling and visualization systems such as 3D Studio MAX and form?” offer increasingly convincing visual simulations, gaming engines are approaching the visual realism of such systems and are offering additional interactive features that are usually available only in more expensive immersive virtual reality systems. Additionally, the capability to have multiple individuals inhabit and navigate the space offers unique opportunities for collaboration as well as the investigation of human behaviour. Participants with internet access can be invited to access a shared virtual environment. Collaboration among users can be further enhanced by combining immersive navigation with peer-to-peer instant messaging and/or adding a voice channel. This paper analyzes these issues through research summary and the creation and user testing of a prototype based on a publicly available gaming engine. Through a series of assignments within an academic course, students in the school of architecture were asked to iteratively use and test this prototype for the collaborative exploration of designed environments. Students made their environments available for others to navigate in real-time and offer comments. A final design review was conducted in which critics were asked to enter the designed environment, explore it at will and interact with the student as well as others present in the same virtual space. This paper will illustrate some of the student projects and describe the immersive,'