2012
Journal article
Restricted
Editorial - ACM Journal on Computing and Cultural Heritage
Scopigno R
Source: ACM JOURNAL ON COMPUTING AND CULTURAL HERITAGE, vol. 5 (issue 2), p. 5
Scopigno R
Source: ACM JOURNAL ON COMPUTING AND CULTURAL HERITAGE, vol. 5 (issue 2), p. 5
See at:
dl.acm.org 
| CNR IRIS | CNR IRIS
2014
Conference article
Open Access
Visual media for Cultural Heritage: an opportunity for assessing, finding limitations and enhancing technologies
Scopigno R
Digital technologies are now mature for producing high quality digital replicas of Cultural Heritage (CH) artifacts. The research results produced in the last two decades have shown an impressive evolution and consolidation of the technologies for acquiring high-quality digital 3D models, encompassing both geometry and color (or, better, surface reflectance properties); technologies for the interactive visualisation of complex models and the integration of different media have been also an important subject of research. In this talk, I will present the more recent progresses, focusing on practical solutions which aim at a major impact in real applications. The talk will also try to give a glance into the near future, demonstrating how geometry processing and visualization could become a major instrument in the study and dissemination of our cultural heritage.
Scopigno R
Digital technologies are now mature for producing high quality digital replicas of Cultural Heritage (CH) artifacts. The research results produced in the last two decades have shown an impressive evolution and consolidation of the technologies for acquiring high-quality digital 3D models, encompassing both geometry and color (or, better, surface reflectance properties); technologies for the interactive visualisation of complex models and the integration of different media have been also an important subject of research. In this talk, I will present the more recent progresses, focusing on practical solutions which aim at a major impact in real applications. The talk will also try to give a glance into the near future, demonstrating how geometry processing and visualization could become a major instrument in the study and dissemination of our cultural heritage.
See at:
CNR IRIS 
| www.cescg.org | CNR IRIS
2001
Conference article
Open Access
A 3D texture-based octree volume visualization algorithm
Boada I, Navazo I, Scopigno R
We present a 3D texture based Octree Volume Visualization algorithm that combines 3D texture hardware and hierarchical representation of data sets to obtain multiresolution renderings of very large data sets. The algortihm exploits advantages of both octree representation and 3D texture hardware. The basis of the algorithm is to take advantage of nearly iso-valued areas of the volume and regions of no interest to compute a more synthetical volume texture representation. A new volume-texture assignation policy allows to exploit 3D texture volume visualization technique on large data sets. The algorithm guarantees hight quality image for regions of maximal interest.Source: THE VISUAL COMPUTER. Plzen, Czech Rep., 2000
Boada I, Navazo I, Scopigno R
We present a 3D texture based Octree Volume Visualization algorithm that combines 3D texture hardware and hierarchical representation of data sets to obtain multiresolution renderings of very large data sets. The algortihm exploits advantages of both octree representation and 3D texture hardware. The basis of the algorithm is to take advantage of nearly iso-valued areas of the volume and regions of no interest to compute a more synthetical volume texture representation. A new volume-texture assignation policy allows to exploit 3D texture volume visualization technique on large data sets. The algorithm guarantees hight quality image for regions of maximal interest.Source: THE VISUAL COMPUTER. Plzen, Czech Rep., 2000
2001
Journal article
Restricted
Multiresolution volume visualization with a texture-based octree
Boada I, Navazo I, Scopigno R
Although 3D texture-based volume rendering guarantees image quality almost interactively, it is difficult to maintain an interactive rate when the technique has to be exploited on large datasets. In this paper, we propose a new texture memory representation and a management policy that substitute the classical one-texel per voxel approach for a hierarchical approach. The hier- archical approach benefits nearly homogeneous regions and regions of lower interest. The proposed algorithm is based on a simple traversal of the octree representation of the volume data. Driven by a user-defined image quality, defined as a combination of data homogeneity and importance, a set of octree nodes (the cut) is selected to be rendered. The degree of accuracy applied for the representation of each one of the nodes of the cut in the texture memory is set independently according to the user-defined parameters.The variable resolution texture model obtained reduces the texture memory size and thus texture swapping, improving rendering speed.Source: THE VISUAL COMPUTER, vol. 17 (issue 3), pp. 185-197
Boada I, Navazo I, Scopigno R
Although 3D texture-based volume rendering guarantees image quality almost interactively, it is difficult to maintain an interactive rate when the technique has to be exploited on large datasets. In this paper, we propose a new texture memory representation and a management policy that substitute the classical one-texel per voxel approach for a hierarchical approach. The hier- archical approach benefits nearly homogeneous regions and regions of lower interest. The proposed algorithm is based on a simple traversal of the octree representation of the volume data. Driven by a user-defined image quality, defined as a combination of data homogeneity and importance, a set of octree nodes (the cut) is selected to be rendered. The degree of accuracy applied for the representation of each one of the nodes of the cut in the texture memory is set independently according to the user-defined parameters.The variable resolution texture model obtained reduces the texture memory size and thus texture swapping, improving rendering speed.Source: THE VISUAL COMPUTER, vol. 17 (issue 3), pp. 185-197
See at:
CNR IRIS | CNR IRIS | www.springerlink.com
2006
Journal article
Unknown
A general construction of barycentric coordinates over convex polygons
Floater M., Hormann K., Kós G.
Barycentric coordinates are unique for triangles, but there are many possible generalizations to arbitrary convex polygons. in this paper we derive sharp upper and lower bounds and use them to show that all barycentric coordinates are identical at the boundary of the polygon. we then present a general approach for constructing such coordinates and use it to show that the wachspress, mean value, and discrete harmonic coordinates all belong to a unifying one-parameter family. but the only members of this family that are positive are the wachspress and mean value coordinates. however, our general approach does allow us to construct several new sets of barycentric coordinates.Source: Advances in computational mathematics 24 (2006): 311–331.
Floater M., Hormann K., Kós G.
Barycentric coordinates are unique for triangles, but there are many possible generalizations to arbitrary convex polygons. in this paper we derive sharp upper and lower bounds and use them to show that all barycentric coordinates are identical at the boundary of the polygon. we then present a general approach for constructing such coordinates and use it to show that the wachspress, mean value, and discrete harmonic coordinates all belong to a unifying one-parameter family. but the only members of this family that are positive are the wachspress and mean value coordinates. however, our general approach does allow us to construct several new sets of barycentric coordinates.Source: Advances in computational mathematics 24 (2006): 311–331.
See at: CNR ExploRA
2010
Book
Restricted
Computer Graphics Forum
Scopigno R.
Computer Graphics Forum is the leading journal for in-depth technical articles on computer graphics. The rapid publication of articles allows readers to keep up to date with new debates and topics of research. The journal features a lively mix of original research, computer graphics applications, conference reports, state-of-the-art surveys and workshops.
Scopigno R.
Computer Graphics Forum is the leading journal for in-depth technical articles on computer graphics. The rapid publication of articles allows readers to keep up to date with new debates and topics of research. The journal features a lively mix of original research, computer graphics applications, conference reports, state-of-the-art surveys and workshops.
See at:
CNR IRIS | CNR IRIS | onlinelibrary.wiley.com
2002
Journal article
Restricted
Dealing with massive volumetric visualisation: progressive algorithms and data structures
Borgo R, Pascucci V, Scopigno R
This article summarises recent results obtained in the area of visualization of massive datasets exploiting the strength of subdivision techniques and distribution algorithms. The focus is on trying to meet storage requirements designing visualisation algorithms suitable for distributed environments.Source: ERCIM NEWS, vol. 51, pp. 46-47
Borgo R, Pascucci V, Scopigno R
This article summarises recent results obtained in the area of visualization of massive datasets exploiting the strength of subdivision techniques and distribution algorithms. The focus is on trying to meet storage requirements designing visualisation algorithms suitable for distributed environments.Source: ERCIM NEWS, vol. 51, pp. 46-47
2002
Journal article
Restricted
Three-dimensional modelling of statues: the Minerva of Arezzo
Fontana R, Greco M, Materazzi M, Pampaloni E, Pezzari L, Rocchini C, Scopigno R
The Minerva of Arezzo is an ancient bronze statue located at the Museo Archeologico in Florence and currently under repair at the Restoration Centre of the Soprintendenza Archeologica of the Tuscany Region. We assembled a complete three-dimensional (3D) digital model of the Minerva before the restoration started. More 3D models will be produced to keep track of the variations that occurred during the restoration process, up to the final acquisition of the form of the restored artwork. The modelling of the Minerva will be the focal point of an ambitious "Minerva Project" that involves the integration of data from other sources in a 3D digital model of the object. Besides this, the project is aimed at showing how 3D techniques can be used to design useful and easily manageable new tools for the diagnostics of archaeological objects. 3D measurements have been realized by means of a high-resolution laser scanner developed at National Institute for Applied Optics (INOA). The instrument is composed of commercial low-cost components in order to be competitive with the very expensive commercial devices. Besides this, our scanner is supported by an efficient and flexible software developed by Consiglio Nazionale delle Ricerche (CNR) that supports all the post-processing phases of a 3D scanning session (range data alignment, merge and simplification).Source: JOURNAL OF CULTURAL HERITAGE, vol. 3 (issue 4), pp. 325-331
Fontana R, Greco M, Materazzi M, Pampaloni E, Pezzari L, Rocchini C, Scopigno R
The Minerva of Arezzo is an ancient bronze statue located at the Museo Archeologico in Florence and currently under repair at the Restoration Centre of the Soprintendenza Archeologica of the Tuscany Region. We assembled a complete three-dimensional (3D) digital model of the Minerva before the restoration started. More 3D models will be produced to keep track of the variations that occurred during the restoration process, up to the final acquisition of the form of the restored artwork. The modelling of the Minerva will be the focal point of an ambitious "Minerva Project" that involves the integration of data from other sources in a 3D digital model of the object. Besides this, the project is aimed at showing how 3D techniques can be used to design useful and easily manageable new tools for the diagnostics of archaeological objects. 3D measurements have been realized by means of a high-resolution laser scanner developed at National Institute for Applied Optics (INOA). The instrument is composed of commercial low-cost components in order to be competitive with the very expensive commercial devices. Besides this, our scanner is supported by an efficient and flexible software developed by Consiglio Nazionale delle Ricerche (CNR) that supports all the post-processing phases of a 3D scanning session (range data alignment, merge and simplification).Source: JOURNAL OF CULTURAL HERITAGE, vol. 3 (issue 4), pp. 325-331
2001
Journal article
Restricted
A low-cost optical 3D scanner
Rocchini C, Scopigno R
Automatic 3D acquisition devices (often called 3D scanners) can be employed to build highly accurate models of real 3D objects in a cost- and time-effective manner. The Visual Computing Group of CNUCE/IEI-CNR has experimented this technology in a particular application context: the acquisition of Cultural Heritage artefacts. Specific needs of this domain include: high accuracy, affordable costs of the scanning device and an improved usability of the data produced. We present the characteristics of a new low-cost 3D scanner, based on structured light, and discuss the first results of its use in a project for the 3D acquisition of a bronze statue.Source: ERCIM NEWS
Rocchini C, Scopigno R
Automatic 3D acquisition devices (often called 3D scanners) can be employed to build highly accurate models of real 3D objects in a cost- and time-effective manner. The Visual Computing Group of CNUCE/IEI-CNR has experimented this technology in a particular application context: the acquisition of Cultural Heritage artefacts. Specific needs of this domain include: high accuracy, affordable costs of the scanning device and an improved usability of the data produced. We present the characteristics of a new low-cost 3D scanner, based on structured light, and discuss the first results of its use in a project for the 3D acquisition of a bronze statue.Source: ERCIM NEWS
2001
Journal article
Open Access
Graphics and visualization: breaking new frontiers (introduction to the special theme section on "computer graphics and visualization")
Òsullivan C, Scopigno R
From the early graphical applications such as flight simulators, to today's stunning special effects in movies, computer graphics have had a significant impact upon the way computers have been used to represent and visualize the world. There are many big problems left to be solved, some of which are reflected in the following pages of this issue.Source: ERCIM NEWS, vol. 44 (issue 6-7)
Òsullivan C, Scopigno R
From the early graphical applications such as flight simulators, to today's stunning special effects in movies, computer graphics have had a significant impact upon the way computers have been used to represent and visualize the world. There are many big problems left to be solved, some of which are reflected in the following pages of this issue.Source: ERCIM NEWS, vol. 44 (issue 6-7)
2004
Conference article
Restricted
Massive data pre-processing with a cluster based approach
Borgo V, Pascucci V, Scopigno R
Data coming from complex simulation models reach easily dimensions much greater than available computational resources. Visualization of such data still represents the most intuitive and effective tool for scientific inspection of simulated phenomena. To ease this process several techniques have been adopted mainly concerning the use of hierarchical multi-resolution representations. In this paper we present the implementation of a hierarchical indexing schema for multiresolution data tailored to overwork the computational power of distributed environments.
Borgo V, Pascucci V, Scopigno R
Data coming from complex simulation models reach easily dimensions much greater than available computational resources. Visualization of such data still represents the most intuitive and effective tool for scientific inspection of simulated phenomena. To ease this process several techniques have been adopted mainly concerning the use of hierarchical multi-resolution representations. In this paper we present the implementation of a hierarchical indexing schema for multiresolution data tailored to overwork the computational power of distributed environments.
2007
Conference article
Restricted
Processing methodologies and interactive visualization of 3D scanned architectures
Scopigno R
Detailed and accurate digital 3D models can be produced with 3D scanning devices, which convert reality into digital form in a cost- and time-effective manner. This document outlines the capabilities of this technology and the overall methodology. In spite of the fact that this technology can be considered sufficiently established, it is not used on a large scale because of a cultural gap and insufficient supply of adequate software to process and render raw sampled data. 3D scanning is still perceived as a complex operation. At the same time, the use of data from 3D scanning in restoration and virtual presentations is below the potential offered by this technology. This brief contribution describes the problems and potential in this field and, at the same time, shows some new software technologies developed by ISTI-CNR.
Scopigno R
Detailed and accurate digital 3D models can be produced with 3D scanning devices, which convert reality into digital form in a cost- and time-effective manner. This document outlines the capabilities of this technology and the overall methodology. In spite of the fact that this technology can be considered sufficiently established, it is not used on a large scale because of a cultural gap and insufficient supply of adequate software to process and render raw sampled data. 3D scanning is still perceived as a complex operation. At the same time, the use of data from 3D scanning in restoration and virtual presentations is below the potential offered by this technology. This brief contribution describes the problems and potential in this field and, at the same time, shows some new software technologies developed by ISTI-CNR.
2008
Conference article
Restricted
Digital sampling of surfaces' shape and color: state of the art and open issues
Scopigno R
New 3D scanning technologies coupled with digital photography allow acquiring accurate and high-resolution models reporting the status of medium (e.g. statues) or large scale artifacts (e.g. buildings). Even if this technology is in a sufficiently consolidated status, its use in real diagnosis and restoration projects is still largely below its potential. This is due to a number of factors; the talk will present the status of the technology and the current shortcomings or issues that make its proficient use in restoration still not very diffuse. The presentation will be based on a number of test cases and will also present some new technologies designed by ISTI-CNR.
Scopigno R
New 3D scanning technologies coupled with digital photography allow acquiring accurate and high-resolution models reporting the status of medium (e.g. statues) or large scale artifacts (e.g. buildings). Even if this technology is in a sufficiently consolidated status, its use in real diagnosis and restoration projects is still largely below its potential. This is due to a number of factors; the talk will present the status of the technology and the current shortcomings or issues that make its proficient use in restoration still not very diffuse. The presentation will be based on a number of test cases and will also present some new technologies designed by ISTI-CNR.
2008
Conference article
Open Access
The CRIMSON project - simulating populations in massive urban environments
Balet O, Duysens J, Comptdaer J, Gobbetti E, Scopigno R
The United Nations recently reported [1] that the global proportion of urban population reached 49% in 2005 and that 60% of the global population is expected to live in cities by 2030. Urbanised areas are extremely vulnerable to all sorts of threats. Indeed, the combination of heavy population concentrations, critical infrastructures and built environments make it possible for environmental, industrial or man-made incidents to rapidly escalate into major disorders. Recent events have forcefully demonstrated that authorities at all levels of government turn out to be inadequately prepared for the intricacies and dilemmas of disasters in large urban environments. Therefore, innovative tools are needed to assist them in the studies, planning and inter-organizational preparation efforts, enabling to understand vulnerabilities and security issues, define and assess crisis management procedures, and train personnel. The CRIMSON research project [2] has been funded by the European Commission in the field of Security Research to address this challenging need by researching, implementing and validating an innovative framework combining the latest virtual reality and simulation technologies. For that purpose, several technological challenges have been tackled by an international team of researchers, industrials and users, and important advances have been made in the following fields.
Balet O, Duysens J, Comptdaer J, Gobbetti E, Scopigno R
The United Nations recently reported [1] that the global proportion of urban population reached 49% in 2005 and that 60% of the global population is expected to live in cities by 2030. Urbanised areas are extremely vulnerable to all sorts of threats. Indeed, the combination of heavy population concentrations, critical infrastructures and built environments make it possible for environmental, industrial or man-made incidents to rapidly escalate into major disorders. Recent events have forcefully demonstrated that authorities at all levels of government turn out to be inadequately prepared for the intricacies and dilemmas of disasters in large urban environments. Therefore, innovative tools are needed to assist them in the studies, planning and inter-organizational preparation efforts, enabling to understand vulnerabilities and security issues, define and assess crisis management procedures, and train personnel. The CRIMSON research project [2] has been funded by the European Commission in the field of Security Research to address this challenging need by researching, implementing and validating an innovative framework combining the latest virtual reality and simulation technologies. For that purpose, several technological challenges have been tackled by an international team of researchers, industrials and users, and important advances have been made in the following fields.
2008
Conference article
Open Access
Three-dimensional digitization: making it easier and extending it to color
Scopigno R
The easy construction of detailed and accurate 3D models is becoming a reality by the increasing diffusion of 3D scanning technology. The reduction in cost of the scanning devices and the increasing availability of good processing tools (including emerging open source solutions) makes 3D scanning an enabling technology for the construction of shape models. The talk will present the capabilities of this technology, presenting some recent advances (low cost scanning systems, 3D-from-images technology, improved automation of sampled data processing) and highlighting some open problems. A major focus will be how color or surface reflection characteristics could be sampled and associated with reconstructed 3D shape models. The different approaches proposed will be reviewed, giving more emphasis to the more practical solutions for both acquiring color or surface reflection and mapping those data efficiently on surface meshes. Some examples of the results of current projects, mainly in the Cultural Heritage field, will be shown.
Scopigno R
The easy construction of detailed and accurate 3D models is becoming a reality by the increasing diffusion of 3D scanning technology. The reduction in cost of the scanning devices and the increasing availability of good processing tools (including emerging open source solutions) makes 3D scanning an enabling technology for the construction of shape models. The talk will present the capabilities of this technology, presenting some recent advances (low cost scanning systems, 3D-from-images technology, improved automation of sampled data processing) and highlighting some open problems. A major focus will be how color or surface reflection characteristics could be sampled and associated with reconstructed 3D shape models. The different approaches proposed will be reviewed, giving more emphasis to the more practical solutions for both acquiring color or surface reflection and mapping those data efficiently on surface meshes. Some examples of the results of current projects, mainly in the Cultural Heritage field, will be shown.
2006
Other
Open Access
La Cattedrale di Pisa nella Piazza dei Miracoli: un rilievo 3D per l'integrazione con i sistemi informativi di documentazione storica e di restauro
Balzani M, Uccelli F, Scopigno R, Montani C
Balzani M, Uccelli F, Scopigno R, Montani C
See at:
ISTI Repository | CNR IRIS
2002
Conference article
Open Access
3D scanning technology: capabilities and issues
Scopigno R
The recent evolution of graphics technology makes it possible to in manage very complex models on inexpensive platforms. These impressive rendering capabilities should be paired with detailed and accurate digita! models. The construction of high quality 3D models is made easier by the increasing diffusion of automatic 3D measuring devices (often called 3D scanners).These allow to build highly accurate 1nodels of real 3D objects in a cast-and time-effective manner. The talk will present the capabilities of this technology focusing mainly on a particular application context: the acquisition of Cultural Heritage artifacts. The peculiar requirements of this domain (high accuracy in the acquisition of both shape and surface appearance, expected low cast and of use of the tools) make it a perfect application example. This talk aims also at presenting and discussing the main issues in the acquisition of accurate 3D models, together with some limitations of current hardware and software tools). Some examples of the results of current projects will be shown.
Scopigno R
The recent evolution of graphics technology makes it possible to in manage very complex models on inexpensive platforms. These impressive rendering capabilities should be paired with detailed and accurate digita! models. The construction of high quality 3D models is made easier by the increasing diffusion of automatic 3D measuring devices (often called 3D scanners).These allow to build highly accurate 1nodels of real 3D objects in a cast-and time-effective manner. The talk will present the capabilities of this technology focusing mainly on a particular application context: the acquisition of Cultural Heritage artifacts. The peculiar requirements of this domain (high accuracy in the acquisition of both shape and surface appearance, expected low cast and of use of the tools) make it a perfect application example. This talk aims also at presenting and discussing the main issues in the acquisition of accurate 3D models, together with some limitations of current hardware and software tools). Some examples of the results of current projects will be shown.
2005
Book
Metadata Only Access
Gestione efficiente dei dati prodotti dai sistemi di scansione tridimensionale
Scopigno R
La ricerca inerente i modelli tridimensionali per le applicazioni ai Beni Culturali (BC) si pone come obiettivo primario lo sviluppo e la sperimentazione di strumenti informatici che mettano a disposizione degli operatori del settore BC un nuovo mezzo di conoscenza: il modello digitale tridimensionale (3D) di un oggetto di interesse storico e/o artistico. Per modello 3D non si intendono, ovviamente, una o più immagini dell'oggetto o, tantomeno, un'animazione ottenuta 'montando' opportunamente immagini fotografiche dello stesso (come è possibile realizzare con strumenti quali QuickTimeVR). Un modello 3D è una rappresentazione digitale fedele e misurabile dell'oggetto in esame ottenuta mediante la rappresentazione esplicita delle sue caratteristiche di forma e colore.
Scopigno R
La ricerca inerente i modelli tridimensionali per le applicazioni ai Beni Culturali (BC) si pone come obiettivo primario lo sviluppo e la sperimentazione di strumenti informatici che mettano a disposizione degli operatori del settore BC un nuovo mezzo di conoscenza: il modello digitale tridimensionale (3D) di un oggetto di interesse storico e/o artistico. Per modello 3D non si intendono, ovviamente, una o più immagini dell'oggetto o, tantomeno, un'animazione ottenuta 'montando' opportunamente immagini fotografiche dello stesso (come è possibile realizzare con strumenti quali QuickTimeVR). Un modello 3D è una rappresentazione digitale fedele e misurabile dell'oggetto in esame ottenuta mediante la rappresentazione esplicita delle sue caratteristiche di forma e colore.
See at:
CNR IRIS | vcg.isti.cnr.it
2005
Contribution to book
Unknown
Surface parameterization: a tutorial and survey
Floater M., Hormann K.
This paper provides a tutorial and survey of methods for parameterizing surfaces with a view to applications in geometric modelling and computer graphics. we gather various concepts from differential geometry which are relevant to surface mapping and use them to understand the strengths and weaknesses of the many methods for parameterizing piecewise linear surfaces and their relationship to one another.Source: , pp. 157–186. Berlin: Springer-Verlag, 2005
Floater M., Hormann K.
This paper provides a tutorial and survey of methods for parameterizing surfaces with a view to applications in geometric modelling and computer graphics. we gather various concepts from differential geometry which are relevant to surface mapping and use them to understand the strengths and weaknesses of the many methods for parameterizing piecewise linear surfaces and their relationship to one another.Source: , pp. 157–186. Berlin: Springer-Verlag, 2005
See at: CNR ExploRA
2010
Contribution to book
Restricted
Modelli digitali tridimensionali: realtà virtuale e paesaggio
Scopigno R
Digital three-dimensional representation of the world had an impressing evolution and start to show a pervasive distribution. A technology which few years ago was common just in research labs is now becoming a common and cheap resource, with both the advent of digital navigation systems entering in our cars or the digital globes our kids are now playing with. The paper presents a brief overview of the methodologies developed for the digital representation of terrains and urban scenes. We present the main technologies for the construction of digital terrain models. Then, we introduce the issues raised by the need of presenting visually those datasets, in the framework of the interactive visualization systems deployed on standard PC-based platforms. The common rendering optimizations, namely geometry culling and data simplification, are introduced; the methodologies and data structures for multiresolution encoding and rendering of terrain data are presented with some more detail. Finally, we present the case of urban models construction and rendering, a topic that is less consolidated than digital terrains but shows an enormous interest in applications.
Scopigno R
Digital three-dimensional representation of the world had an impressing evolution and start to show a pervasive distribution. A technology which few years ago was common just in research labs is now becoming a common and cheap resource, with both the advent of digital navigation systems entering in our cars or the digital globes our kids are now playing with. The paper presents a brief overview of the methodologies developed for the digital representation of terrains and urban scenes. We present the main technologies for the construction of digital terrain models. Then, we introduce the issues raised by the need of presenting visually those datasets, in the framework of the interactive visualization systems deployed on standard PC-based platforms. The common rendering optimizations, namely geometry culling and data simplification, are introduced; the methodologies and data structures for multiresolution encoding and rendering of terrain data are presented with some more detail. Finally, we present the case of urban models construction and rendering, a topic that is less consolidated than digital terrains but shows an enormous interest in applications.