CIPA 2003 XIX th International Symposium, 30 September-04 October, 2003, Antalya, Turkey
model, in order to express, test, modify, and interpret the
hypotheses of the object model before considering them final."
On one hand representation tools are used by the architect to
find a solution to his problem (fig. 1). On the other hand there
is a figuration of the solution. This represents the progress
between problem resolutions. An architect often advances in
the project design through interpretation of his own sketches:
concepts become clear while redrawing continuously starting
from the preceding drawing. The conception is the creation of
a language that is specific to the architect, enabling him to
advance the project. Graphic simulation is then a cognitive
cycle.
Figure 1. Representation of the architectural design process
The work of the designer is limited by the representation means
he regularly uses (plane projections -plan, section - perspective
or axonometric view etc). He may be disorientated if these
means change (Boudon & Poussin, 1988). Figuration is a way
to communicate. It is also a means to convince. The designer
can therefore act on the figuration with respect to the witness as
well as for himself.
The figuration aspect is quite important. It could be realistic or
not. A representation which is not realistic tells about content,
about the concept, contrary to a realistic figuration which
emphasizes the form. The style of the figuration also takes
palace on the message diffusion the representation should give:
a sketch can sometimes be more demonstrative than a
standardized plan. Consequently there exists a ratio meaning /
meant in representation: ratio between what we want to express
and the means which are used to do it (Lebahar, 1983).
There are many means to represent a project. The architect must
choose one. If he wants to represent his project in a total and
realistic way, he will preferably use a 3D view. The point of
view of the perspective can be the same one as this of the
design. The designer can either project himself from a realistic
point of view, or not. There may be an influence of the design
point of view on the final object. One should be aware ol the
liberty the architect has in the choice of his design tools.
2.2. Architectural photogrammetry
There are two fields of applications in photogrammetry: aerial
and architectural photogrammetry. Architectural photogram
metry and aerial photogrammetry do neither share the same
purposes nor the same requirements. Architectural photogram
metry does not require the same high precision software as the
computing units used in aerial photogrammetry. The software
used is often based on multiple view technology. Commercial
digital cameras provide a sufficient resolution for the major part
of architectural photogrammetric applications. Data obtained by
this means is adequate for 3d visualisation, but not sufficient for
metric documentation. The advantage of this software is that it
can run on a PC, allowing the majority of the designers to use it
(Grussenmeyer et al., 2002). With this in mind, a test of
photogrammetry use with low-cost tools was carried out
(Gardiol & Philips, 2001). It aimed at analyzing the precision
of outer and inner building survey with low-cost equipment
(Olympus camedia and PhotoModeler). The study concluded
that it is relevant to use such equipment for surveys of
buildings. Although Architectural photogrammetry is
achievable at a lower cost, management of the processes still
needs to be improved to allow an autonomous use of this tool.
This is a matter of technical knowledge transfer between
technician and user. What is the role of this transfer in the
development of lower cost and lower precision applications
(Fraser, 1997)? Two approaches may be adopted: either the
tools are automated and users do not need training, or use
methods are set up depending on the needs and on the training
capabilities.
2.3. First experiences of photogrammetry use in the
design phase of architectural projects
A link exists between the representation of the survey and the
use of this raw information: "Each convention of representation
implies its spatiality, maybe even its own urbanity" (Latek,
1999). Caution should be taken to avoid that photogrammetry
hinders the design phase, if this means is used during
architectural design. Is it permitted to use documents
characterized by their source, or is it necessary to completely
adapt representation convention to the beneficiary (Eckstein,
2001)?
The use of photogrammetry for an urban project or for a large
project had already been considered. A good example is the
conversion of the Hasanpasa gas works in Turkey (Tanyeli et al,
2001), which demands the restructuring of an industrial area.
Use of Photogrammetry was planned. The challenge resided in
the adoption of a compromise between a precise survey and the
larger study area. Aerial photogrammetry was then chosen. The
collected 3d data was then imported in a software CAD tool:
specific interfaces had to be developed, in order to be able to
process the produced data as classical shapes (plane section etc).
In this case the design method was modified.
The project (Canciani, 2001) is comparable. A three-
dimensional model of town part of Marconi (Italy) was to be
built before being used as a support for the urban project.
The architects’ design method depends on the project context
(Iordanova & Tidafi, 1999). This makes the task very difficult
for those who try to translate those methods in the CAD area. A
part of the built background can be rendered with help of
photogrammetric methods. The representation of this context
thus has an influence on what can be interpreted of it. It is
useful to connect the information provided by these surveys and
existing CAD tools, in order to integrate the photogrammetric
surveys in the architectural project process.
3. ADVANTAGE OF BRINGING CLOSER
PHOTOGRAMMETRY AND THE ARCHITECTURAL
PROJECT
Specifications allow for a clear statement of the problem the
architect will have to solve. This problem is the reference on
which the solution will be based (Prost, 1992). We thus assume
that the problem figuration mode influences the choices of the
designer. The design mode may change if photogrammetry is
used to provide part of the data that is used in the problem.
In this case the architect would get a digital three-dimensional
model to work his project out. The references to architecture are
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