A recent article published in Heritage described a workflow based on a scan-to-building information modeling (BIM) approach to generate a decay map within Heritage Building Information Modelling (HBIM). The workflow was applied to the “Santa Maria della Grotta” church in Marsala (Italy).
From an article in AZO Build by Nidhi Dhull.
Background
Adopting BIM has significantly benefitted architectural heritage management through three-dimensional (3D) parametric models detailing essential information for restoration and conservation procedures. A BIM-based digitalization applied to architectural heritage for preservation purposes is termed Historical or Heritage BIM (HBIM),
However, HBIM has several limitations. Primarily, the BIM framework does not host proper families of objects dedicated to decay mapping or other specific aspects of architectural conservation. This often reduces the degradation mapping process management to a two-dimensional graphical visualization only, without a database where all the decay information can be reported and stored.
Therefore, new applications are required to standardize approaches in the field of HBIM. Accordingly, this study proposed a decay mapping method that works over the 3D BIM model using ad hoc families and a specific abacus created inside the BIM environment.
Methods
A scan-to-BIM-based approach was employed for digitization and thematic mapping of the decay phenomena of the ancient church of “Santa Maria della Grotta.” Apart from the unique sandstone complex of the church, its placement required monitoring methods to preserve the state of the architecture. Therefore, critical issues and a preferable approach were identified before the survey to obtain the best result in the acquisition phase.
A detailed 3D survey using laser scanning technology and photogrammetry was planned to acquire the site’s as-is conditions. A handheld mobile laser scanner (HMLS) was used as an efficient and cost-effective solution for the fast and dynamic acquisition of the whole complex. Additionally, the exterior of the church was captured using a drone.
The acquired geospatial dataset was processed to obtain a complete 3D model of the whole church. The photogrammetric processing was performed through Agisoft Metashape software. Specifically, the software’s Structure from Motion (SfM) algorithm integrated various ground control points to solve the bundle adjustment procedure of the optimization step.
The decay analysis was performed based on the texture information provided by the orthophotos of the church’s internal and external main walls. Subsequently, the survey data was used to prepare a BIM model using Autodesk Revit software. Finally, decay maps were generated over the main surfaces of the HBIM model based on an analysis of the degradations of the building. Subsequently, the decays were mapped according to the International Council on Monuments and Sites (ICOMOS) glossary, assigning a distinctive color and pattern to each degradation for immediate visual recognition and classification of different anomalies.
For the complete article on decay map CLICK HERE.
