La memoria fotografica dell’architettura : restituzioni prospettiche e ricostruzioni

Abstract

This book explores perspective restitution from photographs for the reconstruction of buildings and urban sites that no longer exist or have suffered many alterations over time. Digital drawing and modelling tools overcome many of the limitations that, in the past, made perspective restitution from photographs inaccurate and inconvenient. Traditional drawing tools made perspective restitution from photographs difficult, especially when vanishing points appeared at a great distance from the image frame. The results of perspective restitution were either 1D or 2D objects, i.e. points, segments, angles, planar figures and profiles, that were revolved into the picture plane. By contrast, digital perspective restitution can reach the furthest vanishing point; the orientation of the image can be calculated in 3D space and 3D models can be constructed with the combination of ‘interpretation’ lines and planes; the correspondence between 3D reconstructions and the photographic image can be checked visually by placing a virtual camera at the centre of projection. Digital drawing tools render perspective restitution a powerful tool for scholars involved in the preservation of memory and enrichment of our knowledge of those buildings and sites that had disappeared by the second half of the 19th century, when professional photography became widespread. From its beginning photography recorded urban scenes and monuments; for this reason photographic archives are powerful sources for the documentation of buildings and urban contexts that were either destroyed or changed in the past 150 years, due to conflicts, natural disasters, or urban renewal programs. This book aims to explain the technique of perspective restitution and 3D reconstruction from photographs thus providing a multi-purpose tool for those interested in the study and reconstruction of buildings and urban sites that are documented by photographs alone.