U.S. Department of Transportation
Federal Highway Administration
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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
This magazine is an archived publication and may contain dated technical, contact, and link information.
|Publication Number: FHWA-HRT-07-004 Date: May/Jun 2007|
Publication Number: FHWA-HRT-07-004
Issue No: Vol. 70 No. 6
Date: May/Jun 2007
FHWA demonstrated new visualization technologies for a roadway design process in Montana to improve project delivery time.
|(Above) Shown here is the famed Triple Arches Bridge on the Going-to- the-Sun Road in Montana. FHWA used renovation of the road as a case study in the use of design visualization technologies. Photo: Kevin Gilson.|
Successful completion of a highway construction project depends on actively engaging stakeholders during the planning phase, adequately addressing their issues during the design phase, and clearly conveying the incorporated changes throughout the construction phase. Traditionally, engineers and planners have used two-dimensional (2-D) paper maps (plan and profile sheets and cross-section drawings) to represent the design and construction process. Paper maps fail to engage stakeholders during the planning phase, however, as the maps lack visually appealing three-dimensional (3-D) information. Lack of stakeholder engagement during that phase often results in a cascade of design changes and project delays, as issues raised by stakeholders during construction are incorporated in the project.
Design visualization tools are effective in conveying the real-world 3-D information to transportation stakeholders and the public. When a project involves complex engineering issues, these tools can be used to show proposed designs and to run a series of "what if" scenarios. Inter-action and engagement with stakeholders enables them to provide constructive feedback, understand technical and engineering issues, and be involved in the decisionmaking process.
Design visualization is the simulated representation of a concept and the contextual impacts of a new or rehabilitated highway. The visualization encompasses anything from a simple shaded view within a drawing, to a photosimulation, or even an animated 3-D model. In the past, use of design visualization techniques was limited to large or complex projects due to high cost and computing requirements. The advancement of computing power and availability of moderately inexpensive software, however, makes design visualization tools widely accessible to designers.
The Federal Highway Administration's (FHWA) Federal Lands Highway Division (FLHD) is working to integrate design visualization as a mainstream tool to address design issues and communicate with stakeholders. "The goal is to facilitate the application of simple, low-cost techniques and tools that provide a high relative payback while supporting context sensitive solutions to design problems," says Mark B. Taylor, design discipline leader with FHWA's Central Federal Lands office.
As part of the FHWA technology deployment program, the Western Federal Lands Highway Division (WFLHD) is working on implementing these innovative, emerging, and underutilized design visualization technologies on projects for Federal land-management agencies such as the National Park Service (NPS), U.S. Forest Service, and the U.S. Fish and Wildlife Service. The goals of this technology deployment project are to assess the effectiveness of design visualization tools for a typical situation, evaluate the cost of visualization relative to the complexity of the project, and develop a framework for utilizing these techniques through in-house staff or contracted services.
During an earlier effort, a Web-based design visualization guide (www.efl.fhwa.dot.gov/manuals/dv) was developed for FLHD. This guide documented available design visualization tools and presented a workflow so that the design staff could use such techniques more routinely. The current effort also explores the tools that are not currently available to FLHD staff and are used only by specialized design visualization consultants.
Currently, WFLHD and the NPS are cooperating on the rehabilitation of the scenic Going-to-the-Sun Road, a historic and civil engineering landmark roadway in Glacier National Park in Montana. The challenge and complexity associated with the design and reconstruction of this roadway prompted WFLHD to use this project as a case study for evaluating the role of design visualization technologies in improving project delivery time. (For a full description of the Going-to-the-Sun Road rehabilitation, see "Saving a National Treasure" in Public Roads November/December 2006.)
The reason WFLHD chose the Going-to-the-Sun Road as a case study for design visualization is because the rehabilitation covers a wide range of project issues: road rehabilitation, visitor use improvements, public information, information technology improvements, and transit. The project's final environmental impact statement and subsequent record of decision provided a clear direction for rehabilitation, including a comprehensive mitigation program to minimize impacts on the park and its visitors. One directive called for the development of a new transit system and the integrated deployment of an intelligent transportation systems technology to support the construction, a new transit system, alternate routes, and traveler-related park information.
The Going-to-the-Sun Road project also was optimal for the case study because the rehabilitation involved and affected multiple stakeholders, including WFLHD, the NPS, consultants, park concessionaires, the local tourism industry, gateway communities, and the public. Various changes and improvements to the Going-to-the-Sun Road itself and proposed transit stops needed to be shown to these diverse audiences with special attention to the scenic and historic qualities of the contextual environment.
At the start of the project, the team identified three applicable areas for visualization. The first involved visually capturing the existing conditions along certain parts of the Going-to-the-Sun Road. The second required organizing available data into a more accessible and presentable format, and the third involved simulating proposed design alternatives visually.
The design visualization team used and demonstrated several tools for each of these areas to explain proposed designs for the project. (See "Computer Tools Used for Visualization" on page 28 and "A Comparison of Tools" on page 29.)
|Shown here are two screenshots of a lidar point cloud with color image data applied to the points; the left half of the image shows the color image data, the right the raw point cloud. The scan was taken at a tunnel, the West Portal, of the Going-to-the-Sun Road.|
Documenting existing conditions included simple photography and video. Digital cameras made this easier and more cost effective than in the past. Digital images were used with 3-D model renderings and digital paint techniques to produce photosimulations of proposed changes. For this initiative, the visualization team used Apple® QuickTime® Virtual Reality (QTVR) to produce panoramas for several locations where transit stop changes and improvements were proposed. The images produced a good record of the existing conditions. The images also were used in some locations to produce panoramic photosimulations of proposed improvements.
Computer Tools Used for Visualization
A significant limitation in incorporating visualization into the design process is the wide variety of computer applications and tools used at a typical visualization firm. A key to incorporating design visualization techniques into a design practice involves the commitment to acquiring the tools and applications and enabling staff to learn those applications.
An experienced design visualization practice will have most of the following types of tools: computer aided design/drafting (CADD), geographic information systems (GIS), image processing, three-dimensional (3-D) modeling and rendering applications, and presentation tools. For simplicity, many different types of applications are placed into these five categories. Photography and video also are usually an integral part of design visualization productions.
CADD Tools. Most roadway design projects are developed in a CADD system, and the best way to handle the data is in the native application. For roadway projects, 3-D surfaces can be generated by the design application. Some examples of applications for highway design in the United States include Bentley Systems' MicroStation, Geopak, and InRoads. Accessing design data and preparing for export to other applications can be handled in the MicroStation software. Two important techniques that were demonstrated for the Going-to-the-Sun Road initiative were the 3-D Adobe Acrobat PDF exporter in the current version of the MicroStation software. The other was the conversion of CADD data into overlays for Google Earth Pro mapping service.
GIS. These tools allow different types of data, such as aerials and digital elevation models (DEMs), to be aligned into a consistent coordinate system projection, usually that of the design project. For most roadway projects, a State Plane coordinate system is used for the design work. GIS tools allow data in other coordinate projections to be converted into State Plane coordinates for alignment with design data. A few of the tools that are accessible to design staff are the following:
Global Mapper is a cost-effective tool that allows import, viewing, re-projection, and export of raster images, DEMs, and vector data. This tool was used extensively for the Going-to-the-Sun Road initiative to convert aerial imagery and DEM data into coordinate system alignments that could be inserted into the CADD design files and into Google Earth.
Google Earth Pro mapping service is a software tool that allows the user to see where data are relative to an aerial view of the surrounding context. Google Earth Pro was used in the project as the viewing tool and reference database for all of the existing information collected for the case study: aerials, DEMs, and CADD data. It was used also to visually link to site photography, LIght Detection And Ranging (lidar) scan data, and each of the visualizations produced.
Image Processing. Visualizations are presented as images and usually will involve some postprocessing using an image-based application. Digital painting is an essential part of photosimulation and is used for creation of texture maps — images applied as materials to the surfaces of digital 3-D models. Animation production requires video editing and compositing applications. The project team commonly used Adobe Photoshop® and Corel® Paint Shop Pro® X.
3-D Modeling and Rendering Applications. Visualization will almost always involve some kind of 3-D model for the proposed condition and sometimes the surrounding context. Materials, lighting, and animation are added to a 3-D model using these tools, and then virtual cameras allow the creation of views of the 3-D model. An investment in modeling and rendering software is probably the biggest hurdle to adoption of visualization, due to the cost of the software and the lengthy learning curve. Staff must be dedicated to using the tools close to full time to benefit fully from the time spent learning the software and maintaining a skill level with applications that are changing and improving rapidly.
A certain level of rendering capability is built into MicroStation software, and these tools are more realistic for adoption by highway designers. The learning curve is shorter, and there is an advantage to using the native CADD tools that the designs are being developed in. The roadway designs are turned into 3-D surfaces using MicroStation Geopak tools, and then materials and lighting are added to the 3-D model. Renderings can be generated directly from MicroStation viewports. The renderings can be matched to existing site photos, and image processing software is used to produce photosimulations of proposed projects. This is the technique currently in use by FLHD staff.
Presentation Tools. Included under this category are tools that help in the creation of visualization presentations. Included are applications such as Microsoft PowerPoint presentation software. For the Going-to-the-Sun Road project, a number of other tools were used, including Apple QuickTime Virtual Reality (QTVR) digital media software format to document existing conditions. QTVR files, when viewed in the QuickTime player, were more interactive and descriptive of the environment than static images. The QTVR files were "stitched" from 18 original still images captured on a special tripod head. The image format enabled the viewer to pan and zoom around in a 360-degree view of the scene.
Real-time interactive "game" engines were used in this project for a few presentations. Real-time presentations enabled viewers to move around in and interact within a 3-D environment. This freedom of movement within a model enabled viewers to see what they want from the viewpoint that was most interesting to them, rather than a passive view presented in standard animation where the views and camera path are fixed. Objects, or "layers," in the model could be set to switch on and off interactively, which allowed a direct comparison between alternative model elements from any selected viewpoint.
The performance of real-time models is directly related to the amount of 3-D detail and lighting quality that can be rendered out quickly enough for real-time interactivity. Because of limitations with video and computer system random-access memory (RAM) on standard computers, models used for interactive playback must be optimized for size and number of images employed for representation of the materials in the scene.
Another new technology demonstrated in the study was ground-based LIght Detection And Ranging (lidar) scanning. A lidar camera captured a series of 3-D range values by measuring time of flight for a laser beam to return to the camera several times per second as the lens was moving. This resulted in a set of "XYZ" values, or point cloud, that was translated to a coordinate system that matched the project computer-aided design/drafting (CADD) data. Locations of several of the individual points were measured and turned into usable CADD point or line data. Tools for automating conversion of the point cloud to usable CADD data are evolving rapidly, and this technique will likely become a cost-effective means of capturing existing 3-D project information.
Technology from InteliSumTM, Inc., also was used on this project. InteliSum products incorporate color data into the lidar range data, or point clouds. Each 3-D point from the cloud had several color points, or pixels, associated with it. The tool included a viewing environment that facilitated seeing the data from any view as points or surfaces, either with solid colors or the photographic image applied. This technique was similar to moving a camera around the original 3-D environment, and it proved invaluable for a historically and visually significant project such as the Going-to-the-Sun Road because 3-D and photographic data were captured together in a georeferenced environment (meaning the data are referenced with geographical coordinates).
The InteliSum viewing application enables the user to measure positions for point data and to export sets of point positions for use in CADD applications. "What is interesting about this tool is that other 3-D model types can be inserted into the viewing environment and used to create interactive visualizations showing proposed changes," says Tim Case, project manager with Parsons Brinckerhoff, Inc., the FHWA contractor that produced the design visualizations for the Going-to-the-Sun Road project. Future enhancements to this application will make it more compatible with other point cloud processing software, thus making it useful for capturing existing survey-quality 3-D data while serving as an interactive visualization tool.
A Comparison of Tools
In this table, the visualizations demonstrated in the case study are rated by relative level of production effort and relative software investment cost. They are rated also by the type of expertise needed for efficient use of the tool; a cost-effective tool is not always an easy tool to use economically. Staff may need specialized training or certain inherent skills. The decision on what level of investment to make in integrating visualization into design will depend on the people who will be responsible for production. Dedicating staff full time to visualization production ensures that their skills will be up to date and improve over time.
Most highway designers already are equipped to use the first three technologies (in yellow), and all of these tools are relatively similar in effort required. FLHD staff members currently are producing photosimulations and CADD renderings with animation from MicroStation software. To produce 3-D Acrobat PDF files would require using the newest version of MicroStation software. Renderings from CADD can be used for communicating design issues, cut/fill slopes, and roadway layouts, especially to a technical audience who understands the application renderings and illustrations.
Photosimulations require a little more skill but bring a higher level of realism suitable for less technical audiences. The amount of skill needed and effort spent painting in details is directly related to how much realism is desired for communicating key issues. More complex issues or environments, more controversial projects, and less sophisticated audiences drive the need for more realistic and complex visualizations.
Professional schools are beginning to offer more extensive visualization curricula, so design visualization specialists with the right combination of technical and creative skills will become more available.
A goal of the initiative was to demonstrate a visual, accurate, and collaborative viewing environment that organized and provided intuitive access to project data. GoogleTM Earth ProTM mapping was used for this case study project, but several other tools could have been used to achieve the same result, such as the National Aeronautics and Space Administration's (NASA) World Wind or Microsoft® Virtual EarthTM. These tools provide an environment where users can easily "fly" virtually anywhere on Earth with aerial imagery draped over 3-D terrain data as the base environment. Any data that can be projected in a standard georeferenced coordinate system can be overlaid on this base environment. In the project's early stages, the Google Earth mapping service's aerial data for Glacier National Park was too low in resolution to recognize the roadway. The NPS had high-resolution georeferenced aerials, however, that were imported directly into the model as overlays. CADD data from the design files also were exported in georeferenced format and imported as vectors into the Google Earth mapping service model. Station locations along the road centerline could be selected, and the viewer would "jump" to that location in the model environment.
|This screenshot shows a texturemapped 3-D model of a bus inserted into the color-mapped lidar point cloud. The lidar scan is of the West Portal Tunnel on the Going-to-the-Sun Road|
Location markers, called placemarks, were inserted into the Google Earth mapping service environment. These placemarks could be labeled, contain notes, and be linked to other files. These placemarks were used in the Going-to-the-Sun Road design visualization project to link to site photos, site QTVRs, project documents, and lidar scan locations. A user could open a placemark and reference a QTVR panorama taken from the location of the placemark in the environment. Placemarks also were used to link to other visualizations produced for the case study.
The models produced in these aerial imagery-based presentation tools can be placed in a shared network environment where a project team has access to the same files, or the models can be packaged and distributed for viewing by individuals on their own.
|This screenshot of the Google Earth Pro mapping service model of the Going-to-the-Sun Road includes a high-resolution aerial image overlay. Spatially referenced CADD data from project design files were inserted into the model.|
Other than shaded views produced directly in a CADD environment, the technique that is most familiar to designers for representing proposed improvements is photosimulation. 3-D surfaces for the new roads and grading could be generated using the CADD application and superimposed over existing site photos. With a little work in a digital paint application, the road could be made to look more realistic. Cars and people could be clipped from other images and inserted into the view. For the level of realism obtained, photosimulations were a very cost-effective solution.
Rendered 3-D models were more flexible because they could be viewed from any angle and could include animated elements to give a view more life and realism. All the elements in the scene had to be modeled, and for large projects this could be quite cost prohibitive. Models could be developed, rendered, and even animated entirely in the CADD application in which they were produced. Obtaining the level of realism and quality that could be achieved with rendering applications was difficult, but for projects that do not warrant significant effort, this could be a cost-effective solution. This approach would require some specialized skill or training on the designer's part.
Locations such as the Going-to-the-Sun Road were exceptionally challenging because of the environment's high level of visual quality. Landscaping, curvy roads, and rock surfaces were some of the most difficult features to show and represent well in a model. An area along the Going-to-the-Sun Road called The Loop, the only switchback along the entire route, was chosen as a location from which a highly detailed 3-D model would be produced. The site had many design issues that lent themselves to visual study: a transit stop, major trailhead, parking, and a sharp curve. Several different types of visualizations were produced and compared for this area.
One demonstrated use for the model involved evaluating clearances and visibility with proposed transit vehicles. Because the site model was built from the road design data, and the bus built to scale from the manufacturer's specifications, the two could be used together to analyze and illustrate these issues. The bus model was used in combination with the ground-based lidar-captured data to look at clearances at portals and overhanging rock-face locations along the Going-to-the-Sun Road.
|A 3-D model of a proposed bus was modeled and used for evaluating a new paint scheme. The bus was used in renderings of proposed transit facilities and for checking clearances in 3-D using ground-based lidar scan data.|
Interactive models enable the user to navigate to views that they want to see, as opposed to passive animations or renderings that limit the viewer to fixed views. This flexibility makes these tools useful for both planning changes and presenting designs to a varied audience, such as decisionmakers and the public. Objects in the model can be switched on and off to allow direct comparisons between alternatives. The tools for producing interactive content are becoming more commonplace, and computers today are equipped with sophisticated graphics capability. These improvements will lead to more use of real-time presentations for design visualization.
Adobe® Systems Inc., has incorporated interactive 3-D capability into its Adobe Acrobat® 7 Professional software's Portable Document Format (PDF) file format. The Acrobat 7 Professional software allows the conversion and importation of several different 3-D file formats and has the ability to include the 3-D models in other kinds of documents, such as Microsoft® PowerPoint® presentation software slideshows and Microsoft® Word documents. The recent versions of MicroStation V8 software include an exporter for the Acrobat 7 Professional software PDF format, allowing for direct conversion of 3-D design files into interactive presentations. The format supports texture-mapped surfaces and objects. This tool can be used to view and share project designs. Designers would need to build surfaces and objects in 3-D from their design files to create these presentations, but that involves a relatively small amount of additional work using highway design software applications such as Geopak® or InRoads.
|A highly detailed 3-D model was produced for The Loop area of the Going-to- the-Sun Road. The model was used to evaluate transit stop designs, parking, and pedestrian circulation improvements. Varying numbers of cars and people can be placed in the model to demonstrate safety issues with pedestrian visibility in parking areas during busy usage times.|
|This 3-D model of the site, in combination with accurate 3-D models of the shuttle buses shown here, can be used to check clearances, both horizontally and vertically, along the roadway.|
The video game industry has prompt-ed the development of efficient tools for producing interactive content. Many of the tools are based on the modeling and rendering applications used for design visualization, allowing for a single 3-D model to be used in several ways: rendered views, animation, and interactive presentations. The model that was developed around the Going-to-the-Sun Road's Loop area was used to create a game-like immersive presentation. The user could move around the model to any location and look around. The model included predefined viewpoints and the ability to switch between the existing and proposed conditions, including transit and parking improvements. The main challenge for this type of model was representing the park's scenery as realistically as possible. The plants and rock surfaces needed to be modeled with the least geometry and image information as possible to allow for smooth and effective real-time playback.
The resulting Going-to-the-Sun Road visualizations were presented to Glacier National Park staff currently involved with the transit design work, including Gary Danczyk, project manager, Mitigation, Going-to-the-Sun Road project, who is managing the effort for the Glacier National Park. After seeing the visualization work, he said, "We need to be using these images in our strategic planning meetings for the transit center and bus stops." The presentations will be used for further design evaluations and presentations to other Glacier National Park staff and to the public. The plan is to use some of the mapping tools developed to help visually track and illustrate bus and station locations for a transit control center. The case studies also were presented to the WFLHD design staff responsible for the rehabilitation work, with the goal of using some of the tools for further design studies.
|A screenshot of an interactive 3-D Acrobat PDF inserted into a PowerPoint presentation. The model can be panned, rotated, and viewed from any direction while running the slideshow. The model uses a surface created from U.S. Geological Survey elevation information combined with project survey elevation information. An aerial image has been draped over the 3-D surface. It was exported directly from MicroStation V8 software.|
The Going-to-the-Sun Road visualization study was presented at the Transportation Research Board's 5th International Visualization in Transportation Symposium and Workshop in October 2006. During a panel discussion, titled "Employing Visualization Organizationally," many attendees confirmed the challenge of finding appropriate staff with the right skills to champion adoption of visualization in a design organization. Another recurring panel theme was the common perception that adopting visualization would be cost prohibitive. The symposium's proceedings are posted at www.teachamerica.com/viz/viz2006.html.
A key consideration in finding the right people to help integrate visualization into the design process is having an understanding and awareness of the difference between the visualization artist's creative and technical skills. Some of what makes visualization successful is creative ability, which often can be more valuable than technical proficiency. Visualization technologies vary in their requirements for creative or technical skills. More sophisticated and realistic visualization will require staff members who are interested in, or willing to be trained in, both the creative and technical sides of visualization. Furthermore, they need to be able to include a true representation — unbiased and factual — of the existing and proposed conditions in order to produce a meaningful involvement of the stakeholders.
For the Going-to-the-Sun Road project, a number of design visualization tools were used to explain the proposed designs for several locations. For each unique situation, a specific design visualization technique was selected. The cost and level of effort were compared for various design visualization techniques. The resulting visualizations were presented to the design team and transportation stakeholders, both technical and nontechnical, during several sessions. The consensus opinion of the project design team was that these tools clearly communicated technical aspects of the project and context sensitive design approaches when compared to traditional design plans. "It is a great communication tool to explain various aspects of the project to all stakeholders," says Keith Wong, project manager with FHWA.
The design team was able to communicate the engineering challenges and proposed solution for The Loop to the NPS. The contextual model clearly communicated the visual aspects of the design to the NPS landscape architects. The use of visualization expedited the decisionmaking process to resolve critical engineering issues with the NPS and other stakeholders. In their quest for ontime delivery, designers and managers for the Going-to-the-Sun Road project expressed interest in applying the visualization tools for the planning and design of various phases of this project. "A fully-animated model of proposed transit stop designs at other locations on the road, such as Logan Pass, would be invaluable to show the proposed improvements to our stakeholders and arrive at a consensus design solution in a short timeframe," says Kristin Austin, project design team member with WFLHD.
|An interactive 3-D model of The Loop area, shown here with proposed improvements to the parking and the transit stop. The model was produced with a high level of detail and uses game engine technology for interactive navigation and the ability to switch between existing and future components.|
Amit Armstrong, Ph.D., P.E., is a technology deployment engineer at FHWA's WFLHD in Vancouver, WA. He has been with FHWA for 5 years, coordinating deployment of new, innovative, emerging, and underutilized technologies in design and construction of roads on Federal lands projects. He has more than 15 years of experience in numerical simulation and visualization of natural systems and is a licensed professional engineer. Armstrong received his doctorate in civil engineering from Texas Tech University in Lubbock, TX.
Kevin Gilson has more than 20 years' experience in producing digital design visualization for transportation engineering projects. He is a senior professional associate at Parsons Brinckerhoff, a transportation consulting firm. For the last 2 years, he has been the design visualization specialist responsible for exploring new technologies for the design, planning, and presentation of large-scale civil engineering projects. Gilson obtained a master's degree at the University of California at Berkeley, CA.