MODELLING AND ACCURACY IN A BIM ENVIRONMENT FOR PLANNED CONSERVATION: THE APARTAMENT OF TROIA OF GIULIO ROMANO

A. Adami, B. Scala, A. Spezzoni

Politecnico di Milano, Polo di Mantova, Dept. ABCPiazza D'Arco, 4, Mantova

3D ARCH 2017

WHY BIM FOR CULTURAL HERITAGE

ADVANTAGES:

DISADVANTAGES:

HOW TO MODEL BIM FOR CULTURAL HERITAGE

STANDARDIZATION INSOFTWARE BIM ORIENTED

STUDY CASE:THE APARTMENT OF TROIA, PALAZZO DUCALE, MANTUA

HISTORICAL INTRODUCTION

SURVEY

MODELLING METHODSElement Problem Solution

WALL and WALLCOVERING

DOORS and WINDOWS

DECORATION

FLOOR

CEILING

DATA ORGANIZATION

DATA VALIDATION AND ACCURACY ASSESSMENT

Vault construction process

Photo of the interior of Sala di Troia Point Cloud of the room 3D Model with point cloud

3D View of the Model Vertical section of the Model

Schedule and view of the Model Codification of element modelled

Axonometric view with the point cloud Top view of the map of model accuracy Facade of the map of model accuracy

FROM SURVEY DATA TO A REALISTIC MODEL

vs

of geometric model accuracy

WHY BIM FOR CULTURAL HERITAGE

ADVANTAGES:

DISADVANTAGES:

HOW TO MODEL BIM FOR CULTURAL HERITAGE

STANDARDIZATION INSOFTWARE BIM ORIENTED

STUDY CASE:THE APARTMENT OF TROIA, PALAZZO DUCALE, MANTUA

HISTORICAL INTRODUCTION

SURVEY

MODELLING METHODSElement Problem Solution

WALL and WALLCOVERING

DOORS and WINDOWS

DECORATION

FLOOR

CEILING

DATA ORGANIZATION

DATA VALIDATION AND ACCURACY ASSESSMENT

Vault construction process

Photo of the interior of Sala di Troia Point Cloud of the room 3D Model with point cloud

3D View of the Model Vertical section of the Model

Schedule and view of the Model Codification of element modelled

Axonometric view with the point cloud of geometric model accuracy Top view of the map of model accuracy Facade of the map of model accuracy

FROM SURVEY DATA TO A REALISTIC MODEL

vs

Geomatic fields offers to historic reality the development of methods and techniques finalized to a more in-depth level of detail useful to highlight the uniqueness of elements of cultural heritage. On contrary, commercial BIM software usually works with standardized element, offering the possibility to create ad hoc libraries, more suitable to the reality, but requiring much more time for the elaboration and a high specialized type of user, and losing accuracy in the final model.In the last year, producers of BIM software seem to have been sensitised to the issue of BIM models for historical constructions, introducing the possibility to import point cloud inside modelling environment but operative problems already make difficult their use to model the architecture surveyed.

- Different data in a single Data Base- Interoperable with software for energy simulation, to evaluate potential savings of energy and costs, and structural calculation, to provide information o the state of conservation of the construction- Facilitate management of documents, plans, costs of the building- Overcome the two-dimensional vision, typically used for historical heritage

- Standardization of commercial software BIM-oriented- Enlarged time to obtain a good model- Level of accuracy not always satisfying

The Apartment of Troia is a portion of Palazzo Ducale in Mantua, built on the main floor between 1536 and 1539, the Federico Gonzaga court. Among the several rooms that compose the entire apartment, this work analyses the Sala di Troia, a rectangular room covered by a vault, where Giulio Romano conceives a decoration characterized by an extremely dynamic composition and an illusionistic fusion between walls and the ceiling.

The survey campaign was made by Politecnico di Milano in 2009-2010.The rooms were surveyed by laser scanner (Leica HDS 7000) and the scans were georeferenced in a single reference system on the basis of a topographic survey. For each scan, from the same position of the instrument, it was acquired a panoramic image with fisheye lenses, in order to texture the point cloud.

The model was structured on a work breakdown structure based on the codification used in restoration (organized for technological elements). The codification allows:- to schedule all elements belonging to the same family type- to identify univocally an element modelled inside the 3D model- to establish a bi-univocal correspondence between a single element and its information, which appear on schedules.This data organization makes the BIM model useful for procedures of management of planned conservation.

To validate the process, the model was imported in Cloud Compare, the comparison was made as a difference between the point cloud and the surface and the results can be given to the users as:- a false colour map to link to the surface compared (jpg)- a point cloud to view directly inside the model.In both cases, RGB values represent the distances between the surfaces of the model and the survey point cloud, so that the restorer, who will work directly with the BIM model, will be able to evaluate if the model is suitable for his purpose or if, in specific parts, it will be necessary to create more detailed model.

Survey highlight off plumbs walls, with variable thickness.The element has to belong to the family wall otherwise there would be no hot for wall based families (windows, doors...)

Historical doors and windows presents characteristic shapes that involve the necessity to be defined by more parameters than usual

Presence of low-relief, moldings and spherical cap recesses with no standard geometry

Cloister vault for ceiling Model in-place as ceiling family

The floor surveyed is not plane Stratification of:- Structural layer as a horizontal floor element, with fixed thickness- Finishing layer as a floor element with variable section

Model in-placeNew family wall based

New ad hoc family

Combination of:- Standard Wall element, completely included between the surveyed surfaces- Model in-place as a wall family to cover the gap between the wall surface and the point cloud

MODELLING AND ACCURACY IN A BIM ENVIROMENT FOR PLANNEDCONSERVATION: THE APARTAMENT OF TROIA OF GIULIO ROMANO

A. Adami, B. Scala, A. Spezzoni

Politecnico di Milano, Polo di Mantova, Dept. ABCPiazza D’Arco, 4, Mantova

3D-ARCH 2017