We are developing the Scan & Track virtual environment (VE) using multiple cameras. The Scan and Track VE is based upon a new method for 3D position estimation called the active-space indexing method. In addition, we have also developed the geometric-imprints algorithm for signicant points extraction from multiple camera-images. Together, the geometric-imprints algorithm and the active-space indexing method, pro-vide a promising and elegant solution to several inherent challenges facing camera-based virtual environments. Some of these are: (a) correspon-dence problem across multiple camera images, (b) discriminating multiple participants in virtual environments, (c) avatars (synthetic actors) representing participants, (d) occlusion. We also address a fundamen-tal issue: can virtual environments be powerful enough to understand human-participants.