New techniques constantly seek to meet a growing demand for realistic phototextured 3D models in architecture and archaeology. When only visualisation is required, the emphasis lies on visual quality rather than accuracy. But in architectural photogrammetry the primary requirement is mostly to produce accurate mappings under strict specifications. Hence, accuracy comes first; yet visual products can benefit from precise modeling. In this context, a treatment of cylindrical and conic surfaces is presented. The process for developing them onto the plane (the basic way to represent such surfaces) is outlined and illuminated at the example of two large ancient towers in the framework of projects prepared for the Greek Ministry of Culture. But besides their metric utility, these products represent ideal photo-textures for draping the mathematical surface to generate virtual reality effects. The results of such successful photorealistic visualisations are presented and discussed.