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Title
New perspectives to save cultural heritage
Author
Altan, M. Orhan

TACHEOMETRY IN COMBINATION WITH BUILDING-ELEMENT ORIENTED
CAAD-SYSTEMS
THE INTEGRATION OF HIGH-PRECISION PLAN, SIMPLE 3D-MODEL AND
SUPPLEMENTARY BUILDING INFORMATION IN A SINGLE SYSTEM
D. Donath, U. Weferling
Bauhaus-Universität Weimar, Chair Computer Science in Architecture
donath@archit.uni-weimar.de, ulrich.weferling@archit.uni-weimar.de
Working Group 6
KEY WORDS: precise tacheometrie building surveying, 3D-model, information systems
ABSTRACT:
The use of CAAD systems for surveying historic buildings was previously not possible as such system models were not able to
reproduce the uneven surfaces and deformations inherent in existing buildings. The use of modifiers applied to the standard CAAD-
elements makes it possible for CAAD-systems to respond to the actual plan geometry of existing buildings. This is made possible by
using CAAD-software in conjunction with tacheometrie software on a common working platform (for instance ADT Architectural
Desktop). A 3D-model results directly from the survey and serves as a basis for visualisations, automated calculations (such as
surface areas, volumes etc.) and as a 3D unit of reference for further non-geometric data. The practicability of the process was tested
and exhibited using a real case study object. The main practical advantage of such an approach is the ability to quickly realise a 3D-
visualisation of the surveyed building, in essence a by-product of the survey. This is useful for understanding relationships within
the building and for initial planning studies. It is possible to link the model with further information but the results of this
combination do not fulfil the requirements of a building information system both in terms of performance and usability.
1. INTRODUCTION
Building surveying and documentation in the field of building
conservation and archaeology is characterised by traditional
measurement techniques such as tape, measuring-stick, plumb-
line and spirit-level. They have not been replaced by purely
computer-aided measurement techniques such as tacheometry
and photogrammetry. Instead computer-aided techniques are
often combined with manual methods. However, even
traditional surveying approaches must be oriented towards the
requirements placed on the resulting survey by the future users.
This is becoming increasingly time-consuming when
undertaken using manual techniques:
Very often geometric building surveys are required in
traditional 2D representation as plan, section and elevation with
a high degree of precision and detail. At the same time many
wish to have a 3D representation though rarely at the same
degree of precision and detail. In some cases it is also useful to
combine non-geometric information such as photos or damages
protocol etc. which relate to particular building elements and
can be accessed through a room or object log.
At present each of these requirements is typically addressed
independently of one another:
The plan and section is surveyed using a tacheometer to a
high degree of detail and accuracy,
A 3D-model is then created using the survey data
Non-geometric information is then combined with
geometric model using a database.
All three requirements can however be integrated with one
another using tacheometrie building surveying in conjunction
with a building-element oriented CAAD-system. A pre
requisite is that a CAAD-system can exchange information with
tacheometrie software. At present a handful of CAAD-Systems
- such as ADT Architectural Desktop (autodesk, 2003) or
Palladio X (acadGraph, 2003) - and tacheometrie surveying
systems - such as TachyCAD (kubit, 2003) or EITheo (pms,
2003) - fulfil this requirement using the common work platform
AutoCAD. Using such hardware and software, efficient 3D-
models can be produced with high precision sectional geometry.
2. HIGH-PRECISION TACHEOMETRY AND
BUILDING-ELEMENT ORIENTED CAAD MODELS
The process as described above can in part be achieved using
currently available software products. Different software
modules can be employed in combination with reference to a
standardised working platform (ADT Architectural Desktop by
AutoDesk). Both the CAAD-system Palladio X5 and the
Tachymetry software TachyCAD are conceived as extensions
to ADT and as such can be employed as tools in a platform for
realising the planning-oriented capture of building information.
Of particular relevance is the ability to use the tacheometer as a
3D-mouse (fig. lb) to directly position Palladio X5 elements
(fig la) within an overall coordinate system.
Figure la. Definition of building elements in Palladio X5
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