The design process of a building often involves many different actors and people with different experiences, level of knowledge and ability to interpret information. The most common information media in these processes are 2D-drawings, documents and 3D images of design. These media can be difficult to interpret and understand and could cause communication difficulties and design errors. However, in this context, Building Information Modelling (BIM) and Virtual Reality (VR) have been shown to offer an efficient communication platform. In this paper we present and evaluate a portable immersive visualization system that uses the BIMs directly from the design tools. The system is validated in a real construction project, where the dif-ferent disciplines in the design process used the system. The result was collected through interviews and observation during usage of the system. All the participants expressed that this type of visual interface helped them to get another level of understanding and perception of space, which lead to better decision-making process and resolving of design issues.