CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
m'J«*» jS?** 
•••••••* ••••«•••*¡••«•in.i •m.iY»';**::» ••.•••• •£••»•» 
7“ : ' : .. • ' ;j <• * - .. 
Figure 7 - Segmentation of - the “loggetta” of Sansovina. - 
Venice - Italy 
Figure 8 - solid model of the external walls of the building 
4. SOLID MODELLING 
4.1 Modelling of the segmented point cloud 
After having finished the segmentation stages of the objects, 
it is possible to go on to their modelling. 
This kind of elaboration should be carried out manually 
portion by portion. Many software packages are available on 
the market that offer good performances to 
model a point cloud. 
A specific modelling program was used to prepare the surface 
model that is called Cirrus AC and it is made by Menci 
software. This programme, which works in AutoCAD, is able 
to build surfaces by choosing point cloud portions. These 
surfaces are created using the algorithm for the creation of 
the meshes. 
The thus segmented model was imported into an AutoCAD 
graphic environment and a different layer was assigned to 
each of the portions of the object obtained by the 
segmentation. The modelling of the various aggregations was 
obtained by isolating each portion of the point cloud step by 
step. 
In this way the modelling was particularly simple and quick. 
It was in fact possible to model each part of the model one at 
a time. 
The result of the modelling can be seen in figure 8. 
It is possible to automatically export sections or level curves 
from the thus obtained solid model. 
Another possibility that is offered by modem 3D model 
instruments is the possibility of projecting a digital image on 
a 3D model thus obtaining a coloured 3D model of the object 
and then the orthophoto. 
5. FUTURE DEVELOPMENTS 
5.1 Future Developments 
This article has been written to show some of the first results 
of the segmentation that was performed on archaeological 
objects surveyed using laser instruments. Particularly simple 
instruments have so far been developed by the authors for 
segmenting and models that are available on the market were 
used. This first approach seems necessary to understand how 
to proceed in the research field to segment archaeological 
surveys. 
In the near future it is intended to optimise the segmentation 
techniques, paying particular attention to ground type laser 
scanning. 
This is an application environment where there is still a lot to 
learn because of the recent introduction of sensors that allow 
point clouds to be surveyed.