Surveying and modelling the main spire of Milan Cathedral using multiple data sources

Abstract This paper presents a possible way of surveying and modelling very complex architecture, integrating different instrumentation and modelling methods. In particular, it aims to draw attention to a possible measurement and data processing procedure allowing the rapid collection and post‐processing of data in order to extract classical architectural products such as sections and profiles, and to build complete, accurate 3D models. The need is to structure a multiple data source procedure within a five‐year project (still in progress) to survey and model the main spire of Milan Cathedral three‐dimensionally. The spire is a very complex object and, for this reason, provides a really useful, challenging field test for new 3D survey technologies and, in particular, for integrating a variety of modelling methodologies. The paper describes survey workflow and processing steps, focusing on problems and justifying key choices.