This paper presents a new system that supports automatic path planning for walkthrough in building models, using information retrieved from Building Information Modelling (BIM). It can automatically generate a path that explores all or part of the rooms in a building. During a real-time walkthrough, users will be able to follow the path while interactively controlling their viewing angles. That way, users can take guided tours while simultaneously looking around to examine the spaces. We expect the system to be useful in design review because BIM models of design can be easily brought into the system that allows reviewers to start walkthrough immediately and interactively. The significance of the work is that the system has potential applications for visualization of complex building design.