MULTIPLE USES OF A 3D POINT CLOUD: THE CASTLE OF FRANCHIMONT PROVINCE OF LIÈGE, BELGIUM
A. Luczfalvy Jancsó
a, b,
, B. Jonlet
a
, P. Hallot
c, a
, P. Hoffsummer
b
, R. Billen
a a
Geomatics Unit, Department of Geography, University of Liège, Belgium – aljancso, bjonlet, rbillenulg.ac.be
b
European Archaeometry Centre, University of Liège, Belgium – phoffsummerulg.ac.be
c
DIVA, Faculty of architecture, University of Liège, Belgium - p.hallotulg.ac.be
Commission II, WG II8 KEY WORDS: 3D digitisation, 3D Point cloud, Building archaeology, Visualisation, Integrated survey, AIS, Archaeological
Information System
ABSTRACT: This paper presents the identified obstacles, needs and selected solutions for the study of the medieval castle of Franchimont, located in the province of Liège Belgium. After taking into account the requirements from all the disciplines at work
as well as the problems that would have to be tackled, the creation of a 3D point cloud was decided. This solution would be able to deal with the characteristics and needs of a research involving building archaeology and related fields. The decision was made in
order to manage all of the available data and to provide a common working tool for every involved cultural heritage actor. To achieve this, the elaboration of an Archaeological Information System based on 3D point clouds as a common virtual workspace is
being taken into consideration.
Corresponding author
INTRODUCTION
The medieval castle of Franchimont Province of Liège, Belgium is currently being investigated under multiple angles.
The origins of this cultural heritage site are not well known. Based on the written sources, two hypotheses have been
established dating the beginning of the construction of the castle either to the tenth century or the eleventh century. Over the
course of the next few centuries, the buildings were modified, partially destroyed and reconstructed and new structures were
added. By the end of the eighth century, the castle was abandoned and its ruined state was officially recorded by a
surveyor Hoffsummer, 2016. The ruins of the castle of Franchimont quickly attracted artists
and photographers. This allows for an important iconographic coverage documenting the successive stages of the destructions.
Additionally, the beginning of the twentieth century marks the beginning of archaeological investigations: several researchers
and various sectors have been studied. At the same time, restoration works have been undertaken where it was needed.
For the last fifty years, the Compagnons de Franchimont, a not- for-profit association, has been taken care of archaeological
investigations, restoration works and opening the site for visitors Hoffsummer, 2016.
The University of Liège has been implicated with the research carried out at the castle in various ways, e.g. excavations,
building archaeology and topographical surveys fig. 1.
1. CULTURAL HERITAGE ACTORS
Since the creation of the Compagnons de Franchimont association, interventions have been undertaken regularly on the
cultural heritage site. These may include excavations, restorations, reparations and adapting the site for tourist
purposes. For these various actions, other than the associ ation’s
members, other actors working in the cultural heritage field have been involved.
Figure 1. 3D point cloud of the castle of Franchimont, view from the north-west. The stairs are visible through transparency
as they are located inside of the outer wall. However, these mostly punctual works have not always been
recorded and the data was also not assembled into one common and global documentation system. This has led to multiple data
collections that are not always available to other cultural heritage actors.
1.1 Archaeological investigations
Several excavations and building archaeological studies have been carried out over the years. These are characterized by
different numbering systems over the years, repeating numbers that do not refer to corresponding elements or a common
stratigraphical level. Also, as the excavated sections have been filled in, current analysis can only be executed based on
photographs taken during the digs, on plan and cross-section drawings as well as on the related excavations journals.
However, it can be quite difficult to understand some of the theories and conclusions as they can hardly be verified on site.
Also, the research on this castle is not over yet: new excavations should take place later this year.
This contribution has been peer-reviewed. doi:10.5194isprs-archives-XLII-2-W5-475-2017 | © Authors 2017. CC BY 4.0 License.
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1.2 Architecture
Architects are also likely to be working on the castle of Franchimont. Indeed, some thinking has been done so that some
sectors would be more visitor friendly. As the height differences are quite important and nothing over the first floor can be safely
accessed, various possibilities have been played through. Of course, as this cultural heritage site cannot be modified in its
nature, the architects need to work hand in hand with archaeologists and restorers in order to obtain the most adequate
construction Lilien, 2002. Also, at the beginning of the year 2017, some ideas have been
worked out by architecture students of the University of Liège to make the castle more attractive for tourists. These have been
based on data provided by the newly acquired 3D point cloud as they provide the most recent recording of the whole site and as
it allowed taking measurements in dangerous or inaccessible zones.
1.3
Restoration - conservation
The castle of Franchimont lost its defensive and political power at the end of the seventeenth century. This led to quite
systematic destructions all over the site as the locals reused the building materials. Weather and time erosion also took their toll
on the medieval structures. By the middle of the nineteenth century, the castle of Franchimont was a popular site for
romantic artists and photographers Hoffsummer, 2016. Even nowadays, some parts are likely to collapse. To preserve this
cultural heritage, restoration and conservation works are punctually being carried out.
At the same time, the Compagnons de Franchimont association also supervises reconstruction works based on historical
documents and comparisons with similar cultural heritage sites. This has led to the reallocation of the wall tower at the main
entrance: in addition to its reconstruction, it was transformed in order to welcome the visitors and to provide a small exhibition
hall informing about the history of the site and the discoveries that have been made Hoffsummer, 2016.
1.4
Communication
In order to make the region more attractive for tourists, the castle of Franchimont is an important factor. Therefore, as
previously mentioned efforts are made to render the site and the different structures as accessible and interesting as possible.
With this in mind, a 3D virtual reconstruction has been thought out and commissioned at a professional 3D graphics company.
The castle of Logne Province of Liège, Belgium was previously remodelled by the same firm. The final result,
although it did not present an accurate depiction of the destructed sections, allowed visitors to picture the castle how it
probably may have looked like. The film shown as part of the visit of the site also included the surrounding landscape as it
may have been. The combination of the reconstructed castle and the adapted scenery helps to gain a better understanding of the
impact and the importance that it had while it was still standing Wéry, 2015.
2. NEEDS AND ISSUES
