restitution of the iconographic 
repertory, Of which our monuments are 
very rich, gives us a lot of drawings so 
beautiful as, for certain reasons, 
useless (Fig.l). The synthesis in this 
case is  sclerosed because it loose 
important signs. In this way we are 
bounded to run again through the phase of 
data collection or to go back to the 
object: the photography results to be a 
privileged vehicle, if some well defined 
condition are respected, of infinite 
signs that, only in a second phase will 
be decoded and analized. Also the 
photography permits a natural sinthesys, 
and than the digital photo (Fig.2). 
This is more meaningful if we think to 
the incredible richness of the 
iconographic and decorative patrimony 
that establishes a new object of 
research. With these studies now we have 
the need to trasmit the material and 
formal informations, of which the 
building is the most important support. 
The static-structural stability is the 
"condicio sine qua non" to the maintance 
of these painted and mosaic surfaces. 
We remember the floor of St.Marcus, where 
the knowledge of the geometry 
charaterized by an undulating trend, 
caused by structural movements, is 
strictly correlated to the mosaical 
covering and to the knowledge of the 
state of deterioration visible on the 
parts of the floor decorated with scenes 
or with geometric drawings. 
Therefore it is not possible a clear 
division between the structure  (Brumana 
R., Crippa B., Vassena G., 1990) and its 
surface, more or less formalized.  Infact 
the figure becomes an index of the 
condition of the structure. Therefore 
these are new signs that can be added to 
those ones contained in the shapes in 
whom the surfaces are visible. 
There is so the need of a systematic 
basin of varied informations, numbers, 
drawings. To them are added indexes of 
evaluation of the state of conservation, 
analysis and interventions. 
The process of computerization has open 
even in this branch a lot of 
possibilities, from the control of the 
traditional drawing to the research in 
the field of digital images. 
The electronic archivies re different: 
those ones that collected in a vectorial 
form the various restitutions made with 
lines, the drawings already realized and 
only later the drawings acquired on an 
informatic support; those ones that 
collect the photographic images in a 
raster format (digital images) (Fig.2). 
Now we are studying the positioning and 
the use of the images in the geometric 
three-dimensional space of the 
architectural building. 
    
2 = THREE-DIMENSIONAL SURFACES AND 
DIGITAL IMAGES 
The planning of the research of the 
cataloguing and of the administration of 
the images on one hand, and of the 
representation of three-dimensional 
surfaces, essential support to the 
projection, on the other hand, proceed 
together. 
For the representation of the surfaces, 
we are looking for the possibility to 
arrive at a semiautomatic or guided 
process for the generation of surfaces 
with DTM. In architecture the surfaces 
are usually discontinuous. This 
characteristic is a big handicap for the 
automation that is usually working, with 
some exceptions, to the terrestrial 
ground considered as a continuous surface 
that grows up in the direction of the 
third dimension. The architecture is also 
characterized by some "hidden points”. 
For this reason there is the need to 
change the points of taken and of 
restitution, in the way to make visible 
those hidden parts. 
Let us think to a compex structure like a 
church. From this point of view some 
different applications have already been 
done (Brumana R., Crippa B., Vassena G., 
1990) but it is interesting to point out 
an interesting experience. 
2.1 AN EXPERIENCE ON A SCULPTURE: THE 
DAVID 
We are speaking of the "David", the 
"Gigante" as was suddenly called the work 
of Michelangelo that was begun on the 
1501. 
The metric  surveies were made using of 
the technic of close range photogrammetry 
obtaining the realization of the 
traditional graphic restitution and 
numerical one with lines or  contourn 
lines. Such restitutions allows to 
associate directly into the computer the 
observation already given by the 
restorers through visual analysis and 
those ones given by the diagnostic 
analysis, in the way to obtain some 
specific thematic.mapper. 
Then using of the total photographic 
covering of the statue obtained with the 
photograms, we arrived at the acquisition 
of three-dimensional coordinates of 
points and of lines of discontinuity 
using an analytical stereoplotter. 
Therefore a special data processing, 
Still in a testing phase, for the 
evaluation and the manipulation of the 
three-dimensional solid models  permetted 
the definition of a direct representation 
of the statue (Fig.3).