Currently, public interest in knowledge of urban space has increased as a result of simple aspects such as, for example, more kilometers traveled with vehicles, greater personal energy consumption, increased air pollution, increased cost of public transportation services, decreased natural resources, among others.
This increased public interest is supported by municipal or metropolitan leaders and authorities, who seek to better coordinate land use in environmental, sociological and economic terms.
3D Urban Modeling implements a new perspective on the dynamic process of urban development, resulting from the interaction of various influences on decision-making in land use, zoning and transportation.
3D models are generally created using special software applications called 3D Modelers. Typically, these models are derived from a collection of data (points and other information), obtained through a manual process, an algorithm, or using a scanner.
Engineering uses 3D models to study new products, vehicles and spatial structures, as well as a prototype of the final version. In the 2000s, with the advent of technologies such as image correlation and LASER Profiling, the geosciences community began building 3D models of the earth's surface as a common practice.
3D visualization models have a variety of applications in Cartography and urban studies, such as: Site Situation Analysis, Emergency Planning, Urban Zoning, Urban Volumes for Environmental Studies, Marketing, Tourism, etc. Even though they are generally used simply to visualize the built environment, there are applications such as 3D interfaces to more sophisticated simulation models.
Significant advances have been made in the development of "intelligent" 3D models. Currently available technology makes it possible to detail and simulate urban environments in a way that makes interaction easy for the standard user. 3D models can be used both as a user-friendly interface for interacting with the urban environment within a GIS for links to information on the Internet, or in a more complex way, to create functional simulation models.
3D City Models from CAD
This type of modeling is the most common example of a 3D urban model, with several applications already existing in many cities around the world. These models depict cities or urban environment scenes in three dimensions with varying degrees of detail and artistic interpretation.
3D CAD models are often presented as animations, screen captures, and navigable VRML environments. Normally, the models have no functionality beyond display (that is, they are not linked to a spatial database, nor are they capable of displaying a query result on demand). In addition, they can be "navigable" by the operator or purely static. Applications for these models are diverse, ranging from advertising to project review.
3D City Models from GIS
In a way, these are models identical to CAD models; sometimes they are generated using the same type of software. The difference, however, lies in functionality.
While the 3D CAD model offers the operator no functionality beyond simple display, incorporating a Geographic Information System (GIS) into a 3D visual model empowers the user to perform specific queries about the buildings and built space depicted in the model environment.
A GIS essentially acts as a spatial database with a graphical interface for performing queries, operations and manipulations on data in an interactive environment. 3D GIS models introduce this functionality (if data is available) to the 3D CAD model. Operators can query the built environment and have the results displayed visually and interactively in three dimensions on screen. For example, an operator might want to discover where there is available space to set up an office by comparing rental prices and structural characteristics in a city center. Or, for example, determine the influence of urban structures on the transmission of a directional signal from a given point and within a range, as in 3G phone transmissions and directional FM and microwave transmissions.
Navigable 3D City Models
Technically, when watching an animation, each scene or image must be assembled in terms of more or less complex polygons. So, the more complex or textured the scene, the longer the required rendering time.
A "real-time" experience refers to an interpretation of the 3D model at a rate of 30 images per second, which comes closest to simulating reality. Scenes in real-time visualization are at such "speed" because the emphasis is on putting the user in front of a dynamic experience with maximum interaction. Every time the operator moves the cursor over the image, its perspective changes. As the response must be fast, more complex textures, such as terrain and facades, are often represented by overlaid aerial or ground photographs on the model's skeleton.
In general, navigable 3D urban systems tend toward "real time" because of their freedom of movement, ease of use and ability to quickly generate alternative scenarios.
Examples of 3D urban modeling generated by ESTEIO:
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Video of Belo Horizonte/MG built in Google Earth, using height as the Z value of building vectors. (medium-resolution files to facilitate viewing – MPEG file, 9.2 MB)
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Video of Belo Horizonte/MG built in ArcGIS, performing extrusion via the attribute table. (MPEG file, 6.8 MB)
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Niagara video built in Terra Photo, using the LASER point file, building construction, RPC files for tree rendering, and the orthophoto. (MPEG file, 2.2 MB)
Capabilities
ESTEIO carries out the following services:
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Terrain and Surface Modeling using Airborne LASER;
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3D Modeling of Urban Solids using Airborne LASER or Photogrammetry;
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Spatial Analysis based on Urban Volume;
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Thematic Maps supported by 3D Modeling;
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Virtual Navigation in 3D Environment.