Home Articles 3D has designs on urban modelling

3D has designs on urban modelling


GEOFF ZEISS
Director, Autodesk Geospatial Technology

The world is facing serious challenges including climate change, aging infrastructure, shrinking workforce and lagging productivity.

In industrialised countries, the challenge is crumbling infrastructure and replacing unsustainable structures and the impact of economic downturn. This needs to be checked by speeding up and increasing infrastructure spending at various levels of government. In emerging economies, development of new and sustainable infrastructure poses the challenge.

NEW DESIGN TECHNOLOGIES
To address these challenges, architects, designers and engineers are adopting new technologies. The business drivers for these transformative technology advances are productivity and efficiency in the entire lifecycle from design, build, through operate and manage.
Most of the world’s buildings and infrastructure like roads and highways, power, water and waste water, telecommunications and oil and gas pipeline networks were traditionally designed using CAD desktop applications. The objective of this CAD approach to design is a paper drawing, but increasingly architects and engineers are adopting a model-driven approach to design that results in an intelligent representation of a building, bridge or any other structure. In architectural design, this is referred to as building information modelling or BIM. Many people in the industry are convinced that BIM not only reduces the cost of design and construction for new structures, but can also significantly reduce the downstream costs associated with operation and maintenance.

Another important trend in IT in the last five years is geospatial enabling, which simply means making applications location aware. For example, all the major search engines like Google and Yahoo now incorporate location so that searches almost always result in an option to view a map using Google Earth, Google Maps or Yahoo Maps. All major relational database management systems including Oracle, MySQL and Microsoft SQL Server now support spatial data types. Architectural and engineering design applications are now able to support real world coordinate systems. The important drivers for integrating geospatial with engineering and architectural design are local government regulation, for example, right to light, noise abatement and view protection, sustainability objectives like maximising green space, reducing impervious cover, eliminating heat islands, maximising natural lighting and reducing energy use and emissions.

Once the preserve of gamers, 3D simulation technology is now an important tool used by architects and engineers to experience a building or other structure during the design


phase itself. 3D simulation relies on many of the same 3D visualisation and simulation technologies underlying computer games and allows architects and engineers to convey their designs more effectively, reduces the risk of major modifications to built structures and enables optimisation of buildings and infrastructure for their full life-cycle including operations and maintenance.

The integration of these key technologies including model driven design, geospatial enabling and 3D simulation provides high quality visual environment and analytical framework that enables seamless access to architectural and engineering design, traditional GIS, new data sources such as laser scanning and high resolution photogrammetry and transportation, utility and telecommunications network data inside, outside and under a facility.

"An important trend in IT in the last five years is geospatial enabling, which simply means making applications location aware. All the major search engines like Google and Yahoo now incorporate location so that searches almost always result in an option to view a map using Google Earth, Google Maps or Yahoo Maps"

URBAN MODELLING

But these new technologies are not only changing how we design, build, operate and manage buildings and infrastructure, but are enabling the intelligent 3D precision simulation of entire urban environments.
The data required for a seamless view of an urban environment already exists in precision digital form, in the form of CAD drawing files, BIM models, utility and telecommunication network infrastructure databases, LIDAR and traditional GIS data. Integrating precision engineering data to deliver a precise synthetic environment that can be used to simulate the inside (utilities, HVAC systems, furniture, elevators, walls, doors, windows and structural details), outside (aerial utilities, full city blocks of 3D detail, road access) and under (underground water, wastewater, gas, power, and telecommunications systems) of an urban environment creates an intelligent model that can be used for visualisation, analysis and simulation. For example, urban simulation can be used to analyse the load impact of a new building on a utility network, how the building will shade the surrounding area at different times of the day and year, how much daylight will be available in interior spaces at different times of the day and of the year, how noise from a nearby sports stadium will impact residents of the building and how the building will affect traffic patterns.

A 3D simulation of an urban development before it is constructed enables citizens to experience and understand how the development will impact them in a much more intuitive


way than is now possible. Cities trying to attract new business are finding that a 3D model is able to demonstrate in an intuitive manner the advantages of a particular location in terms of proximity to services such as transportation networks and hubs, recreation and educational facilities. In the past twenty years, many of the world’s largest cities like the City of Vancouver and engineering firms like Parsons Brinckerhoff have developed 3D models using applications like 3ds Max. Developing these models required sophisticated modelling techniques and skills that are not accessible to smaller municipalities.

Technical advances are now making 3D urban modelling available to a much broader market including medium to small municipalities. New software applications for integrating engineering design data, utility, transportation and communications networks, traditional GIS data and data captured using high resolution photogrammetry and laser scanning are making it possible for a much broader range of users to create and deploy 3D urban models to the desktop and across the Web.
As an example, let’s walk through the process to create a digital city from existing data, add visual effects to the digital

" New software applications for integrating design data, utility, transportation and communications networks, traditional GIS data and data captured using high resolution photogrammetry and laser scanning are making it possible for a broader range of users to create and deploy 3D urban models to the desktop and across the Web"

model and use it to do analyses and create images/2009/march and animations using a desktop digital city modelling application called LandXplorer.
The first step in creating a digital city is typically to begin with a digital terrain model. Land Xplorer allows you to import terrain models in a variety of formats, for example, grid formats including Arc/Info Grid, Nasa SRTM, GeoTIFF, Erdas Imagine and USGS DEM. To give the terrain a more realistic look, raster images/2009/march can be added as terrain textures from aerial photography, satellite imagery and scanned maps in a variety of formats including GeoTIFF, ECW, MrSid, JPEG2000, and PNG. Terrain textures can be blended to provide more information. Level of Detail 1 (LoD1) building models can be created by extruding simple building footprints prepared in AutoCAD, ArcGIS, Microstation or MapInfo using building heights stored in an attribute table.

To make building blocks more realistic, individual buildings can be accessed and the properties of each building edited, for example, by choosing different generic roof types. Existing 3d vector files can be imported to create LoD2 buildings with discrete roof, wall and floor entities using data from ESRI 2D and 3D Shape, GML and CityGML files. LoD3 georeferenced buildings can be imported from 3ds Max, X3D, and Collada which contain realistic details and building facades generated from digital photographs.
Non-georeferenced 3D models of bridges and other structures can be added and positioned on the surface by dragging and dropping. Point data such as the location of busstops or vegetation can be imported and symbolised using images/2009/march or 3D models.
The second step is to make the digital model more visually compelling adding generic building facades to the building blocks. The textures of individual buildings can be edited, for example, to change the depth of the texture to better fit the


building. Terrain texture can be draped on the roofs of buildings. Dynamic skies including cloud movement, cloud density, sun elevation and light intensity can be added and adjusted to simulate different lighting conditions. Water shading information can be added from CityGML files to give the impression of a dynamic body of water including reflections of structures and clouds in water bodies.

The digital model can be packaged and made available for visualisation as well as analysis and simulation. Information generated during the planning process can be imported from existing data sources, for example, a planned development footprint. Rules-based actions can be used to thematically analyse the building models, for example, to find and colour all the residential buildings in the project area.
Utility infrastructure data can be imported, scanned development plans can be dropped onto the terrain for better understanding of the planned simulation and proposed building models can be added by extruding building footprints from engineering or architectural drawings. Distances to neighbouring structures can be measured to help understand the impact development would have on the surrounding

"Director, Autodesk Geospatial Technology 35 MARCH 200 9 GIS DEVELOPMENT Static digital images/2009/march and video animations can be created for presentations using a variety of techniques including trackball, free flight, typical paedestrian navigation, 3D-panning, directed flight using visual bookmarks and camera paths"


environment. Finally, static digital images/2009/march and video animations can be created for presentations using a variety of techniques including trackball, free flight, typical paedestrian navigation, 3D-panning, directed flight using visual bookmarks and camera paths. More images/2009/march of 3D digital cities created using these techniques can be found at . com/ showroom.aspx. In summary, 3D modelling is no longer just for ‘big cities’. Technical advances have made this technology available to a much broader market including small to medium-sized municipalities who may have felt that in the past that 3D urban modelling was out of their reach.