The generation of 3D models of sites and objects requires a methodology able to deliver reliable and precise results with all the geometric and radiometric details of the surveyed scene. Nowadays the surveying techniques employ passive or active sensors, alone or in an integrated mode in order to exploit all the advantages of each technique. Reality-based 3D models are used in many applications like mapping, monitoring, documentation, conservation, animation, planning, heat dispersion estimation, etc. The article reviews the most common surveying techniques and 3D modeling issues before presenting different examples of projects running in FBK.