Currently, immersive virtual reality is experienced through head-mounted displays while the user is physically present into a real, cluttered environment. This causes the problem of avoiding dangerous collisions with obstacles in the real environment that are invisible to the user, and also hampers the interaction with real objects. Following the augmented virtuality paradigm, these obstacles should be embedded into the virtual environment. Thus, there is the need of knowing the 3D structure of the real environment to align it with the virtual one. In this paper, we present a method to create a virtual scenario composed of virtual objects having the same spatial occupancy of the corresponding real ones. The real scene is scanned to detect the position and bounding box of objects and obstacles, then virtual elements having similar spatial properties are added to the virtual scene. Two different real environment structure detection and clustering techniques are described and compared, both quantitatively and by considering users’ sense of presence with respect to the standard Chaperone technique. Our results show that the method is a good solution to maintain the real environment awareness while keeping an high level of immersivity and sense of presence.