Digital city models for civil design

February 2013 » Exclusive
Expansive, 3D city models developed for project planning, design, delivery, and outreach
Andrea Barry, LEED Green Associate
Continued use and expansion of Parsons Brinckerhoff's Seattle 3D city model has made it the world's largest above and below ground model of its kind.
Image: Parsons Brinckerhoff

Fifty years ago, 30 percent of the world's population lived in cities. Today, for the first time in history, more people live in cities than in rural areas. This number is expected to grow significantly during the next 20 years, and continue into the future.

With this rapid urbanization, design firms are considering adaptive re-use and smart growth measures to overcome the considerable set of challenges imposed on disciplines such as transportation, infrastructure, air and noise quality, energy efficiency, water resources, carbon emissions, and brownfield redevelopment. To address these challenges while navigating today's environmental and design processes, design professionals must rely on digital design tools to inform decision making and communication across disciplines.

Parsons Brinckerhoff, a global consulting firm assisting public and private clients to plan, develop, design, construct, operate, and maintain infrastructure projects, has been using 3D design tools to aid with project communication, management, and collaboration for years. Taking traditional 3D project models a step further, Parsons Brinckerhoff has begun to develop expansive 3D city models to meet a broad range of goals and deliverables.

The deployment of city modeling for project planning, design, delivery, and outreach presents an easy-to-use, integrated 3D environment for its users. And yet, there is considerable complexity behind the scenes combining a variety technologies, data repositories, and applications. Common uses for these city models include:

  • analyzing and communicating design alternatives;
  • evaluating the performance of character studies for specific areas within a municipality;
  • visualizing new and proposed public and private development;
  • determining the contextual impact of open space, urban design, and infrastructure improvements;
  • evaluating transportation and mobility scenarios; and
  • exploring "what if" scenarios during planning to evaluate viability and gain consensus.

Parsons Brinckerhoff has digital modeling efforts in multiple cities including New York, Denver, San Francisco, and Los Angeles. One of the most relevant case study examples is a 3D digital city model of Seattle, Wash.

3D city models can accurately communicate technically complex projects to a wide variety of audiences using high-impact deliverables such as photo simulation.
Image: Parsons Brinckerhoff

In 2004, Parsons Brinckerhoff had numerous public agency and private-sector urban development projets in and around downtown Seattle that required 3D visualization and visual communication services. Clients had one common request: Show their project in the context of the surrounding environment.

This request stemmed from a desire to show project impact and visibility, as well as to promote the benefits and amenities of projects through 3D renderings and animations. The city model grew organically as Parsons Brinckerhoff continued to model city context around its projects. The visualization team catalogued the city, identifying each block on a map, and gradually modeled sections of the city, taking photographs of the specified block to provide realistic textures and materials for the model.

This practice led the team to leverage GIS data from the City of Seattle to develop an underground model of Seattle's infrastructure in support of the Washington State Department of Transportation's State Route 99 Alaskan Way Viaduct Replacement program. The Alaskan Way Viaduct project is replacing an existing seismically vulnerable elevated viaduct with a bored tunnel under downtown Seattle. Due to placement of the seawall, existing utilities, building pilings, and an underground bus and light rail tunnel, the tunnel will be as deep as 200 feet to avoid conflicts with these structures. The underground city model was critical in making design decisions and communicating the design to project stakeholders.

With the continued use and expansion of the Seattle 3D city model, it has become the world's largest above and below ground model of its kind. Originally, the model was used primarily for visualization purposes. Today, it has evolved into a mega database of information that spans from downtown Seattle to the University of Washington campus, across Lake Washington and into the City of Bellevue. This significant undertaking has leveraged many authoring tools and software such as Autodesk's AutoCAD, 3ds Max, Navisworks, Civil 3D, and Revit, in addition to GIS data, to ensure technical accuracy and a high level of photo realism.

The model was recently utilized by the Seattle Housing Authority (SHA). SHA is engaged in a comprehensive planning effort to replace the aging Yesler Terrace public housing buildings with a new mixed-income community, where people can come together to enjoy cultural diversity and high-quality housing with amenities close by.

Parsons Brinckerhoff leveraged the 3D city model to incorporate the 30-acre site development concept for the Yesler Terrace project by SHA with its prime location adjacent to downtown Seattle. The overall site was modeled as building blocks with suggestive elevations, textures, and materials, and with additional pedestrian-level details being incorporated along the major corridors of Yesler and Broadway. These details include suggestive landscaping, street design, retail, and other commercial businesses.

Additionally, the improved neighborhood connections and proposed streetcar are featured and highlighted. Key viewpoints in and around the project were highlighted in the final 3D animation to demonstrate the tremendous view corridors. The visualization is being used to inform and educate various audiences about the overall scope, scale, and vision of the project, while promoting informed communication with project stakeholders. The 3D model will continue to evolve to support the project as planning decisions are made and development deals are secured, providing further return on investment to SHA.

As new infrastructure and urban development projects evolve with the rapid population growth in our cities, changes to the urban landscape become too large and occur too quickly to allow planners and policy makers to react efficiently using traditional planning tools. Digital city models have the ability not only to bring together multiple data sets from various design and operational databases, but also to allow designers and decision makers to proactively and rapidly test design scenarios that evaluate viability.

The underground model of Seattle's infrastructure was critical for avoiding conflicts with a seawall, existing utilities, building pilings, and an underground bus and light rail tunnel during design of a bored tunnel for the Washington State Department of Transportation's Alaskan Way Viaduct Replacement Project.
Image: Parsons Brinckerhoff

Further, the models accurately communicate these technically complex projects to a wide variety of audiences using high-impact deliverables such as photo simulation, 3D renderings and animation, real-time interactive and immersive environments, Web-based interactive tools and applications, and mobile applications. Digital city models can be leveraged on many project types including:

  • Environmental Impact Statement support;
  • model-based visual view impact study;
  • real time shadow/light analysis;
  • visual representation of noise levels simulations;
  • design alternatives and scenarios comparison matrices;
  • constructability review of infrastructure projects;
  • carbon emissions studies;
  • traffic simulations;
  • urban design and surface improvement;
  • disaster simulations;
  • egress modeling and evacuation;
  • urban-scale computational fluid dynamics;
  • zoning studies;
  • energy efficiency and metrics; and
  • city skyline impacts and evolution of the skyline over time.

As our society continues to embrace the advancement of technology, multimedia, and mass communication, with the desire to be informed and connected at all times, visual communication will continue to be of paramount importance. Digital city models allow for the output of large amounts of multi-faceted data that can be widely dispersed quickly; understood clearly; and retained through images, animation, and interactivity.

View two videos developed from Parsons Brinckerhoff's Seattle 3D city model to visualize the Yesler Terrace and Alaskan Way Viaduct Replacement projects at

Andrea Barry, LEED Green Associate, oversees business development for Parsons Brinckerhoff's Project Visualization Practice Area. She is responsible for developing key client relationships, managing pursuits, client consultation, and presenting the group's capabilities to local, national, and international audiences. Additionally, she serves as program manager/principle in charge on large private-sector and urban development projects in which the group leads. Jay Mezher, AIA, leads Parsons Brinckerhoff's National U.S. Virtual Design & Construction Group, where he is responsible for managing projects and staff. His responsibilities include leading the Parsons Brinckerhoff VDC/BIM Global Task Force and the global Practice Area Network for VDC, 3D/BIM modeling support, 3D design integration, temporal and/or spatial clash detection, 4D modeling, 4D modeling with analytics (cost or risk), rendering, and animation.

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