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A RESEARCH PROJECT IN THE INTERSECTION OF ARCHITECTURAL 
CONSERVATION AND VIRTUAL REALITY: CAHRISMA 
Z. Karabiber Yüksel, C.Binan, R. Unver 
Yildiz Technical University, Faculty of Architecture, Istanbul, Turkey - (karabi, runver)@yildiz.edu.tr, binancb@tnn.net 
KEY WORDS: Heritage, Virtualisation, Architecture, Conservation 
ABSTRACT: 
CAHRISMA - “Conservation of the Acoustical Heritage by the Revival and Identification of Sinan’s Mosque’s Acoustics’’, research 
project carried on within the Fifth Framework INCO-MED Programme of the European Commission, is designed by the goal to 
innovate the acoustical heritage concept in the field of architectural conservation. The main objectives of this research are 
identification, revival and conservation of architectural heritage in a new way. Objective and subjective evaluations and audio-visual 
reconstruction of Sinan’s Mosques and Byzantine Churches in interactive 3D virtual environments are the basic approaches of the 
project. Virtual restoration, virtual conservation, and determination of different significant acoustical effects are the main results. In 
this paper CAHRISMA Project which takes place in the intersection of architectural conservation and virtual reality is presented. 
1. INTRODUCTION 
Conservation of the cultural heritage covers all sorts of efforts 
to protect and transfer the historical document in its all 
authenticity to future. That' s why, conservation of the 
architectural heritage includes the presentation of the artwork to 
the society by all its different dimensions and past usages, 
besides the protection. There are three phases of the 
architectural work. First phase is the construction and 
utilization of the building for an identified function where every 
kind of hardware and elements are present to serve the function. 
The second phase starts soon after the first one and lasts during 
the whole life of the building. The rate of the alterations that an 
architectural work sustains throughout the second phase differs 
upon cultural and social environment. However it is not easy to 
expose this historic stratification on a protected and utilized 
building. The recent situation of the building where we met and 
interfere to the architectural heritage depending on the 
conservation concepts and principals is the third phase. The 
point of view at the third phase is different; the building is more 
then a simple coverage of human activities, it is an historical 
document and a mirror to the social and cultural development 
process. 
The aim of the CAHRISMA Research Project is the 
presentation of the architectural heritage to the community 
beside its physical being that we met at the third phase. To 
illustrate the different layers and stratifications of the 
architectural heritage has always been a difficult task because of 
the concerns about possible harms on the physical structure of 
the work. It is not always possible to illuminate all of these 
features by drawings and texts and moreover this method is 
generally only comprehensible by experts. By the developments 
of computer technology, it is now possible to recreate 
environments belonging to one of the different periods of the 
building in virtual reality and present it together with the 
artificial environment visualising the cultural features of the 
related period. Till nowadays these works were limited to visual 
perception, however it is possible to recreate different 
environments effecting human' s various perceptions. 
CAHRISMA, ‘The conservation of Acoustical Heritage by the 
Revival and Identification of Sinan’s Mosques’ Acoustics’, an 
interdisciplinary research project carried on within the EC Fifth 
Framework INCO MED programme, will provide one of the 
pioneering products in this field. CAHRISMA is a three-year 
project, started in February 2000. The participants of the project 
are Yildiz Technical University-YTU (Turkey), Technical 
University of Denmark-DTU (Denmark), Università degli Studi 
di Ferrara-UNIFE (Italy), École Polytechnique Fédérale de 
Lausanne-EPFL (Switzerland), University of Geneva-UNIGE 
(Switzerland), AEDIFICE (France) and University of Malta- 
UOM (Malta). 
Basic goals of the CAHRISMA Project are identification, 
revival, and conservation of the combined architectural heritage 
(visual + acoustical heritages) in a real time virtual 
environment, like one Time Machine. This project supported by 
European Commission will open new dimensions having 
boundaries difficult to dream within the architectural 
conservation concept. 
For the realisation of the mentioned goals, three Sinan’s 
mosques from 16 th Century; Kadirga Sokullu, Siileymaniye, 
Selimiye and three Byzantine churches from ll lh Century, 
SS.Sergius and Bachus, Hagia Eirene (St. Irene), Hagia Sophia 
(St. Sophie) are selected as the worship spaces to work on at the 
project. These worship spaces are well known for their good 
acoustical qualities. 
This paper aims to present the CAHRISMA Project which takes 
place in the intersection of architectural conservation and 
virtual reality, spotting that the acoustically supported virtual 
restitutions would be one of the major steps to transport the 
architectural heritage to the future. 
2. METHODOLOGY OF THE PROJECT 
Advanced interdisciplinary and trans-disciplinary features 
should be used in the identification and conservation of the 
‘Combined Architectural Heritage’. A methodology that will 
have apparent benefits both in identification and conservation 
fields has been developed in order to transfer the ‘Combined