RICERCA ITALIANA     

Integrated Methodologies for the Survey, Drawing, Modelling of Urban and Architectural Environment.

Università degli Studi di Roma "La Sapienza"

Abstract

The term “digital revolution” has been very used in these last years in order to identify the deep changes affecting all human activities and much more those connected with the scientific research.
If on one side we have experimented a nearly immediate passage from the “pre-digital” procedures to the new ones (sometimes even sacrificing researchers’ flexibility to systems’ rigidity), on the other we have not registered yet a “feed-back” motion aiming at integrating the pre-digital procedures as well as the development of more ergonomic ways in the human-data interaction.
This issue appears to represent a major task in the field of survey, documentation and, more in general, of knowledge of the architecture and the city: beside the recalled problems, in fact, the pressure put on researchers by the extraordinary technological innovation (especially determined by 3D scanning development) has somehow revolutionised the consolidated concepts of “survey” and “modelling”.
As the research aiming at optimizing the application of the illustrated powerful technologies represents a major priority, on the other hand it’s equally important to recover the traditional “heritage” in such a way to make it compatible (and consequently comparable) with the information acquired with the most advanced methodologies.
This matter is significantly dealing with the “Model” concept, that is with the set of operations that lead to the discreetization of architectural and urban complexity according to variable parameters.
Both graphic representations on different supports (graphic models) of our deep and recent past as well as the most advanced ones, by now commonly stored in a digital form on CDs or DVDs, actually appear to be homogeneous from this particular point of view and only await for a “unification” procedure.
Together with the problems typically connected to 3D Modelling (acquired data interpolation, primitive and surface construction, morphological and superficial analisys, etc.), present project aims at setting up a methodology capable in integrating and comparing not only the information acquired within the same time period even with different techniques (3D scans, instrumental, photogrammetric, direct surveys, etc.), but also that coming from previous campaigns (even very far in time) up to the original design.
Furthermore, the project will investigate new ways for communication and dissemination of gathered and elaborated data, both experimenting real-time interactive exploration systems and testing the opportunities coming from multimedia production software.
The whole of these activities is besides following the strategic research line constantly carried on by the same research group in the last ten years: a consistent number of publications and interventions at national and international level well demonstrate the matter. <<<

Principal Investigator

Mario Docci Università degli Studi di ROMA "La Sapienza"

Research Objectives

The deep changes we have been experimenting during these last ten years owing to the capillary diffusion of digital systems have greatly affected the field of Documentation and Analysis of the architecture and the city.
If on one side we have experimented a nearly immediate passage from the “pre-digital” procedures to the new ones (sometimes even sacrificing researchers’ flexibility to systems’ rigidity), on the other a counter-balancing “feed-back” motion aiming at integrating the pre-digital procedures as well as the development of more ergonomic ways in the human-data interaction is still to come.
This question appears to represent a major task in the field of survey, documentation and, more in general, of knowledge of the architecture and the city: beside the recalled problems, in fact, the pressure put on researchers by the extraordinary technological innovation (especially determined by 3D scanning development) has somehow revolutionised the consolidated concepts of “survey” and “modelling”.
As the research aiming at optimizing the application of the illustrated powerful technologies represents a major priority, on the other hand it’s equally important to recover the traditional “heritage” in such a way to make it compatible (and consequently comparable) with the information acquired with the most advanced methodologies.
This matter is significantly dealing with the “Model” concept, that is with the set of operations that lead to the discreetization of architectural and urban complexity according to variable parameters.
Both traditional representations on different supports (graphic models) of our deep and recent past as well as the most advanced ones, by now commonly stored in a digital form on CDs or DVDs, actually appear to be homogeneous from this particular point of view and only await for a “unification” procedure.
Together with the problems typically connected to 3D Modelling (acquired data interpolation, primitive and surface construction, morphological and superficial analisys, etc.), present project aims at setting up a methodology capable in integrating and comparing not only the information acquired within the same time period even with different techniques (3D scans, instrumental, photogrammetric, direct surveys, etc.), but also that coming from previous campaigns (even very far in time) up to the original design or graphic and iconographic sources .
In this framework we can however distinguish three priorities which, merging together, actually concur to reaching the general project goal:
- A Scientific and technological goal, aiming at developing, according to previous ideas, innovative procedures for construction and manipulation of 3D Models coming from 3D scans or other acquisition techniques.
The research activities will so concentrate on acquisition and reproduction techniques, in order to make them faster, reliable and flexible in reconstruction and integration with different information.

- A Methodological goal, aiming at focusing and developing new methodologies and utilisation fields for acquisition and reproduction techniques: as a result, a general improvement of operational present protocols will be obtained as well as the definition of new usage hypothesis.

After this initial analysis some foreground methods will be selected in order to the following project objectives:
3D Model features construction and control – Numeric data coming from the “point cloud” is the interpretation basis leading to geometric properties of any surveyed surface. Transformation of raw data and their refinement have to be both investigated and improved with special attention to ‘decimation’ (controlled reduction of needed points for complete surface description), interpolation and smart recognition of simple surfaces and discontinuities protocols.

Predictive study of surface characteristic – Together with geometric parameters, 3D scanners measure the response grade in any single point (reflectance): this datum, strictly linked to superficial condition and nature of the object,
has already demonstrated an important potential in prediction both of conservation state and material first estimation.

Knowledge/Dissemination – This topic again represents a foreground issue of this project: in the scientific field (many experts can contemporarily share object’s information in any part of the world) as well in the tourist and teaching one. We can in fact imagine interactive workstations which can be used by the public to explore generally unreachable or not visible parts owing to restoration, maintenance, etc. A study will also set up in order to explore the possibility of interaction through mobile phones as well as through holographic representation techniques.
A major task will finally concern reproduction potentials of material replicas techniques using CNC equipments CAD/CAM interfaced or 3D printers.

Data Integration - Suitable storing and consultation procedures result as a major objective for this project: as applying architectural-and-urban-complexes-oriented GIS systems, as finally investigating new on-line sharing approaches like the 3D Browsing technology.
In this frame a particular focus will be put on making comparable and compatible the information acquired with the most advanced survey techniques and that coming from different collections of graphic and iconographic sources.

- An application task , finally, where some developed procedures will be tested and validated on real study cases: these will be chosen within the Mediterranean area by all URs depending of their relevance to project’s goals. <<<

First Results

Although the development of present research represents a coherent whole of concurrent activities, nevertheless a number of major results can be listed. They actually refer to the three main tasks described in the proposal (Task 1 – Scientific and technological issues, Task 2 – Procedures and Methods, Task 3 – Testing and dissemination):

Task 1 – Scientific and technological issues.
This scientific and technological task aims at developing innovative procedures for construction and manipulation of 3D Models coming from 3D scans or other acquisition techniques.
From this task we expect a relevant increase of basic knowledge concerning the instruments themselves and their management; on the other hand, though, a productive feed-back process between research institutions and manufacturers will be set up in order to reach an overall improvement of existing equipments as well as the development of new ones. Inside each proposal coming from the 5 Research Units of this project, is possible to retrieve the number and quality for the relationships set up with different manufacturer and developer in this sector.

Task 2 – Procedures and Methods.
This strictly methodological task, will deal with focusing and developing new methodologies and utilisation fields for acquisition and reproduction techniques: as a result, suitable operational protocols as well as new usage hypothesis well be defined.
It represents somehow the core of the project: the main part of results, both on the theoretical and operational side, are then expected during this phase. Beyond the set up of methodologically correct procedures, a number of virtual 3D models will be acquired, constructed and elaborated according to the research line expressed by each Research Unit.
All these elaborations could form a first national kernel for data responding to a common methodological standard being in the meanwhile open to further additions or integrations.
Some of these examples will be used for testing the previously illustrated on-line dissemination techniques.

Task 3 – Testing and dissemination.
The last activity planned in the frame of this project will concern the testing and validation of some developed procedures on real study cases: these will be chosen according to the specific research lines defined by all URs depending on their relevance to project’s goals and characteristic.
This part of the project will be essential for achieving some crucial operational results:
- Refining and validation of the procedures developed within the project.
- Application to relevant real cases in order to create a sort of Best Practice repository.
- Partial reports on local research on the Internet and in the proceedings of meetings. Publication of the final research report on journals and conference proceedings. <<<

Timescale

24 months

National and international background

The term “digital revolution” has been very used in these last years in order to identify the deep changes affecting all human activities and much more those connected with the scientific research.
If on one side we have experimented a nearly immediate passage from the “pre-digital” procedures to the new ones (sometimes even sacrificing researchers’ flexibility to systems’ rigidity), on the other we have not registered yet a “feed-back” motion aiming at integrating the pre-digital procedures as well as the development of more ergonomic ways in the human-data interaction.
This question appears to represent a major task in the field of survey, documentation and, more in general, of knowledge of the architecture and the city: beside the recalled problems, in fact, the pressure put on researchers by the extraordinary technological innovation (especially determined by 3D scanning development) has somehow revolutionised the consolidated concepts of “survey” and “modelling”.
As the research aiming at optimizing the application of the illustrated powerful technologies represents a major priority, on the other hand it’s equally important to recover the traditional “heritage” in such a way to make it compatible (and consequently comparable) with the information acquired with the most advanced methodologies.
This matter is significantly dealing with the “Model” concept, that is with the set of operations that lead to the discreetization of architectural and urban complexity according to variable parameters.
Both graphic representations on different supports (graphic models) of our deep and recent past as well as the most advanced ones, by now commonly stored in a digital form on CDs or DVDs, actually appear to be homogeneous from this particular point of view and only await for a “unification” procedure.
The question is quite complex, and addresses not only a solution, but an organic investigation capable to put in full light its specific terms. In order to design the heterogeneous scientific framework of this research proposal it is useful to start from this very opened question.

The terms of the problem.
At the centre a few technological and methodological problems can be listed: on one side they relate to the data acquisition, management, organization and employ; on the other to the strategies of integration between the information acquired by means of digital technologies and that coming from the traditional graphic and iconographic documents. And although each of these questions involves a specific scientific frame the analysis of these will lead to a comprehensive understanding of the state of the art.

Data Acquisition
This specific problem is strictly connected with the sampling technologies.
The traditional survey procedures, direct, instrumental and photogrammetric (either computer based or not), have recently been subject to a true revolution connected with the development of 3D acquisition new tools (3D Scanning). This innovative technique leads to the generation of points clouds which represent a regular spatial sampling of the acquired surface.
Such new technology, thanks to its amazing sampling speed (up to several points per second) allows for the first time in history, to build 3D virtual models of complex and extremely large objects (projects carried on by the research units include Rome’s Colosseo and Pantheon, and the Hagia Sophia in Istanbul, S. Pietro in Vaticano), with extreme accuracy (with an error tolerance of a few millimetres). Such models can furthermore be geo-referenced contextually with the aid of GPS systems, which determine the earth coordinates of the scanner’s station points.
Nevertheless, the 3D scanning technology was mainly developed for military and industrial scopes. Here continuity and geometrical legibility prevail, whereas on the contrary, surface non-regularity and discontinuity is a typical trait of the artefacts to be found on architectural/monumental and urban contexts, raising questions about specific hardware and software improvements.

Data management.
The data gathered with the innovative methods we have been talking about, merge towards the construction of the 3D model of the architectural or urban element under investigation. The process is all but automatic, and involves a number of definite steps:
- The raw data deriving for the cloud of points, which can be seen as the reference for the geometric features of the artefact, need to be transformed and refined. This process is still carried on by percentage ‘decimation’ of the existing points, with a limited possibility to weight independently different surface areas (an average planar surface can be represented with a smaller number of points than a more geometrically complex surface). Similarly the possibility to take advantage of ‘intelligent’ automatic discontinuity recognition functions is also limited.
- Similar opened problems pertain the procedures for generating high resolution 3D models referring to a number of different single scans, that need to share a unique and common reference system. The alignment of several “range maps” can produce wrong measurements of the final model, dramatically reducing their potential degree of accuracy.
The full understanding within the integration of 3D models with different data sets, such as digital photographs, photogrammetry, spectrophotometry, colour sampling data and so on also needs deeper investigation.
All the research units participating to the present proposal have been investigating strategically the set of problems that this document addresses and share the understanding of the central role taken in this process by the building of the 3D virtual model, as the nucleus for merging the date needed to build a multidimensional database of an artefact.
Data Organisation – In the last ten-year periods, the methods of the historical, architectural and urban research have really changed, even as for registration systems. Moreover, architectural and urban researches are more and more contextual and have to expand on a vast scale and to manage a big number of data. The large amount of plants, drawings, prospects and views makes hard the analyses fort the scholars.
That is why it has become necessary to establish a system to manage easily the data and to process them quickly in an whole and open frame, the Multidimensional Database, that succeeds in recording many kind of multimedia data (texts, numbers, bi- and tri-dimensional drawings) divided in single objects. The model has to include spatial and temporal dimensions to allow the projection in different temporal fields in Unit or Units Site space.
As a result we have a multi-scale system that can record, manage and analyse data coming from different kind of research. Such system gives to the final user the possibility to view and analyse the data both in macro (context) or micro scale (single element analysis).
Data consultation and utilisation – Problems referring to this field are connected with any scientific research representing a major independent task.
In our case, though, it becomes the actual benchmark for testing all developed approaches.
Together with consultation problems (presently all features are very scarce comparing with digital systems potentials, as well user interfaces which are not enough user friendly) we still register an actual difficulty in consulting digital and non-digital documents at the same time. In survey and documentation field, in fact, the non-digital information, often coming from centuries of studies and measurements, greatly exceeds the digital one. Besides, the comparison between this type of data is based on the process of transformation of the digital information in the non-digital one (as an example you can consider the plotting of a survey to make it comparable with an ancient drawing), while the opposite flow is extemporary and underused: an improvement in this sector would then determine a better exploitation of on-line navigation techniques, as well as a recover and re-contextualizing of the graphic and iconographic information of the past.
Recently appeared 3D Browsers and advanced visualisation and interaction open though real interesting research perspectives referring to context we’ve been describing:
the state of the art in the development of such technologies present the combination of a relevant improvement of graphical performance with the enhancement in the capability to edit and manage events, behaviours, constrains, animations, the interaction with archives and databases. With the consequence of highlighting the potential added value of the merging between a true 3D database, advanced visualization capabilities. and hypermedia interactive narrative patterns. Such platforms ease the access to complex data structures (text, images, animations, drawings, photographs and so on), that are extremely versatile and can be assembled in a very intuitive fashion. Due to their capacity to give access to a vast range of information, simply by clicking on a 3D model component, 3D model based information systems represent an improvement of traditional approaches towards information-access, and disclose new directions to the idea of direct data manipulation of and of the ‘exploration’ of an information set. <<<