Visualizing a better future

October 2009 » PROJECT CASE STUDY
Accessible 3D modeling and 4D simulation enhances collaboration among project stakeholders.
Adam Strafaci
Photorealistic visualizations helped diffuse community concerns and perceptions about the impact of the proposed Presidio Parkwa

Today’s high-profile, multi-stakeholder transportation infrastructure projects are more complex and demanding than the simpler road design jobs of the past. To meet the demands of these new projects, many engineers are adopting building information modeling (BIM) — an integrated process for exploring a project’s key physical and functional characteristics digitally, before it’s built. Supplementing and sometimes replacing their traditional 2D design and drafting software with newer 3D and 4D tools for model-based design enables civil engineers to create coordinated, reliable design information. With this information engineers can respond to design changes faster, optimize projects with visualization and simulation, and produce higher-quality designs and construction documentation.

At Parsons Brinckerhoff (PB), model-based design has become a necessity as the company’s role has evolved beyond just designing roads and transportation infrastructure. PB deals with public constituencies where visualization — enabled by a model-based workflow — helps to communicate the design intent to the average person who may not get the idea from conventional drawings. Even among diverse public bodies involved in a project, it is common for agencies to have conflicting ideas about a design. Visualization and simulation of an infrastructure model can help resolve such differences and smooth the way for faster project approvals.

A case in point is Doyle Drive, a $1.045 billion project to replace the south access to the Golden Gate Bridge with a new Presidio Parkway. Designed and built in a less contentious era, the existing Doyle Drive opened in 1936 as a direct route from San Francisco’s Marina District and Palace of the Fine Arts, through the Presidio to the bridge toll plaza. The original road has outlasted its useful lifespan with respect to traffic capacity, seismic resistance, and overall roadway condition. Other conditions have changed as well. The Presidio, in which both the existing drive and proposed parkway are located, has transitioned from a closed-to-the-public army post into an actively used part of the Golden Gate National Recreation Area. Public attitudes also have transitioned regarding urban and natural environments, roadways and recreation, and community participation in public decision-making.

The Doyle Drive project team at PB has strived to create a roadway that reduces impacts to biological, cultural, and natural resources; respects the project setting within a national park, the National Historic Landmark District, and surrounding neighborhoods; meets community needs; and provides a safer roadway. Clearly, there is more at stake in the Doyle Drive project than can be encompassed by civil engineers’ traditional profiles, centerlines, and contours. That’s why PB is moving to 3D and beyond for design and visualization throughout its collaborative process for the Doyle Drive replacement project: to better understand how the design will perform; assess its impact on the surrounding area; and virtually identify and resolve issues before they become costly mistakes.

Advanced workflow
The Doyle Drive project team is somewhat unusual in nature. The project client — California Department of Transportation (Caltrans) — is also doing the roadway design, while a joint-venture between consultants Arup and PB is handling the environmental and architectural aspects of the project, along with project communications. Within PB’s 12,000-person organization across 150 offices world-wide, the Project Visualization Group (PVG) is a 50-person service line that provides all aspects of media for PB—from visualization and motion, to virtual design and construction (VDC) and web presence.

This project’s organization structure presented the team with workflow challenges, but afforded innovative workflow opportunities as well. PB aggregated data from 2D CAD files and sheet files into 3D models. Some Caltrans-produced design files, such as 3D roadway surfaces, could be moved directly into PB’s 3D/4D workflow, but most output from Caltrans’ standard Autodesk CAiCE transportation software came to PB in 2D formats. The 2D output required a kind of “pre-processing” into 3D via Autodesk’s AutoCAD Civil 3D model-based software. Once in a 3D format, the data was sent by PB/PVG from CAD to Autodesk 3ds Max software via DWG. A model was simultaneously built to go to 4D simulation in Autodesk Navisworks software and for further development in visualization.

PB’s 4D simulations and detailed construction sequencing in Autodesk Navisworks helped give the team the ability to view and analyze during early design stages, and provided a holistic way to evaluate design and construction. This process also enabled PB to provide valuable design-stage feedback to Caltrans without forcing the client to change its established internal 2D workflow.

Further development in visualization, headed up by Mark Kaufmann, a technical lead at PB, included more than 70 tasks/requests from within the team. These included 3D drive-through animations to evaluate alternative lighting designs in day and night views. Visualizations were also created to study architectural elements, such as retaining walls, signage, and landscaping at the tunnel portals, where the proposed parkway will burrow under — rather than cut through — the Presidio environment.

Getting the picture
The latter point touches on another critical project benefit from PB’s 3D/4D workflow. A picture is worth a thousand words, especially when certain words carry loaded connotations. Although the Presidio Parkway design was the “preferred alternative” among 24 schemes studied in 10 years of design and planning, some community groups labeled the design “a freeway through the Presidio.” Popular inference from those words might have led to negative perceptions based on freeways in general, whereas 3D visualizations of the parkway design helped to clarify the difference for the community and defuse the issue.

Renderings of the existing Doyle Drive (left) and proposed Presidio Parkway (right) help designers and other stakeholders better understand how the design will perform and assess its impact on the surrounding area.

Whether the end product was a 3D animated visualization (check it out at www.doyledrive.org) or a 4D simulation, Autodesk 3ds Max served as a hub of PB’s workflow on Doyle Drive, offering such flexibility that it would have been difficult to do this project without it. As models were developed in 3ds Max, the team could break them up into construction tasks, which helped provide better support for Navisworks 4D simulation when linked to the construction schedule. A master 3ds Max model posted on the project intranet site was replicated so that PB had multiple camera views for numerous visualization tasks and requests.

Drive-through animations were used to evaluate alternative lighting designs in day and night views.

While PB used 3ds Max as a hub for its workflow, VDC Engineer Tristan Randall found innovative uses for Navisworks, even extending beyond its role in 4D schedule simulation. For example, Randall developed a process that used Navisworks to help link and track the more than 70 visualization tasks/requests on the project website. In a sense, PB used Navisworks to manage the visualization project itself, as well as the underlying Doyle Drive project.

All gain, little pain
Although the official metrics won’t be in until after the first phase of construction, PB is optimistic that the value of contract change orders (CCOs) as a percent of the bid price will be reduced for the Doyle Drive project, when compared with typical Caltrans projects. The presumption is that 4D will lead to better project understanding, therefore tighter bids and fewer surprises and CCOs.

From a workflow perspective, PB has benefited from enhanced collaboration among project stakeholders. Having an accessible 3D model as a central part of the information on this project has helped improve the company’s relationships with the other stakeholders. All those involved reacted positively to the ability to be transparent and have total visibility into every aspect of the project.

(left) PB’s 4D simulations and detailed construction sequencing in Autodesk Navisworks helped give the team the ability to view and analyze during early design stages, and provided a holistic way to evaluate design and construction. (right) A master 3ds Max model posted on the project intranet site was replicated so that PB had multiple camera views for numerous visualization tasks and requests.

Brady Nadell , P.E., is project manager for Parsons Brinckerhoff. He can be contacted at nadell@pbworld.com. Adam Strafaci is senior industry marketing manager for civil infrastructure at Autodesk, Inc. He can be contacted at adam.strafaci@autodesk.com.


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