Most large construction projects use some kind of 3D modeling through their various stages—whether it’s CAD, BIM, photo simulations, or another technology. But sometimes finding a way for the project team and the public to fully grasp a design concept takes something a little more interactive in nature. In Kentucky, a recent highway interchange project brought this kind of animation to a new level, or at least a different one for traditional engineering.

Aerial view from the game, in which the diamond pattern is clear.

In 2011, the Kentucky Transportation Cabinet (KYTC) constructed a new type of highway interchange, called a “double crossover diamond” or DCD, in Lexington, a first for the state. This innovative design directs left-turning traffic toward the left side of the intersection—crossing over opposing-side traffic in a diamond pattern—thereby improving capacity and reducing congestion. Because the pattern is an unconventional one, the design team developed a series of 3D models and animations for the first public meeting, helping drivers better understand how vehicles enter the intersection and move through it.

The interchange proved to be a huge success, prompting the KYTC to move on to a second double crossover diamond effort, this time at an interchange of interstate I-75/ I-71, and KY 536 in northern Kentucky, about 15 miles south of Cincinnati, Ohio. Seeing how helpful the 3D models were the first time around, the KYTC definitely wanted to again use the technology to communicate with the public.

During a public meeting for another section of the project, Bob Yeager, Branch Manager for Project Development at KYTC  said, “If we could just take everyone, put them on a bus and drive them down to Lexington to see a DCD in person, they would understand it immediately. Why for that matter, we could let them drive the bus themselves!” That’s when the light bulb went on for the animation designers—maybe the team could let people “drive” through the intersection, virtually.

The idea was to develop an interactive video game that actually lets people drive through a virtual version of the interchange. That meant not only figuring out how to create the game and translate the 3D animation design process for it, but also convincing the team it was the right tool for the job.

“There was a minor concern about the limited budget we had for graphics,” says Stantec project manager, Brian Aldridge. “So we weren’t sure we could pull off the feat and make it worthy of public release.”

Stantec’s design visualization team had been dabbling with the Unity video game software for some other projects and proposed it as a potential tool for this interchange effort.

Unity posed a number of benefits:

  1. It’s cheap. Typically, video game engines are developed and owned by video game studios at a cost of tens of thousands of dollars. Unity, however, costs only $1,500 for a license.
  2.  It’s an open-source platform. Built on that open-source premise, Unity fosters a community of developers who build game components you can purchase and plug-ins that allow you to make real-time changes. What’s more, if you need a particular feature or have a problem with the software, this open-source community can offer advice or solutions.
  3. It’s easy. The learning curve is small for a 3D visualization artist using a tool like 3ds Max with Unity. Essentially, the team could build the scene in a 3D model, importing all the information directly from 3ds Max into Unity.

And because the project was in the preliminary design phase, they could start from scratch using both tools, integrating them through as much of the design process as possible. Fundamentally, the two tools do the same thing, but technically they are opposites. 3D animations involve hardware- and computation-intensive technologies, while video gaming requires as light a footprint as possible since the capabilities of the end users’ computers could range widely. Unity served as a bridge between the two—the full 3D model could be optimized for Unity for faster game play as well as completed in a 3D program with full detail.

Cars approach the intersection from the left side of the road, as seen here. The game helped show drivers how easy and intuitive that approach actually is.

Knowing they had both end products in mind, the team started the design in both 3ds Max and Unity using project site terrain data and the actual interchange design data until the point where the level of detail diverged. For a 3D animation, details like terrain, road curves, cars, and trees need to be as realistic as possible to hold up to heavy scrutiny during approvals. For the video game, however, the team could import elements like cars and trees built to be light and functional rather than ultra-realistic.

Having the ability to essentially design the two public involvement products in parallel saved a tremendous amount of time and money. Even better, the synergy between the two programs allows for live updates to both. So if the engineers make a change to the highway alignment, the animation team can make that change to both files at once by modifying one model.

At first, the team designed the video game to replicate the driving experience as realistically as possible, employing controller steering wheels that provided as much rotation as the steering wheels in real cars. They soon realized, however, that anyone accustomed to playing video games was also used to accommodating the much narrower steering radius of video game controls.

In other words, in a video game, a few degrees of rotation turns the car much more than in real life. The team wanted to make sure that the video game truly was the right tool for educating the public on the new interchange and not simply an entertainment piece in which drivers could veer off course at their whim. With that in mind, they reprogrammed the game for that narrower steering radius and developed predetermined paths so drivers couldn’t run off the road. Keeping the drivers on the right path kept the focus on learning how the new interchange works.

The video game was a hit with users at the public meeting where it debuted. The team did notice a bit of a generational learning curve in the user population; those under the age of 45 or so had grown up with video games and drove the game very well, while older folks spent more time adjusting to the sensitivity of the wheel. But quickly those drivers, too, were impressed with how the game’s accuracy and excited with how easy driving through the interchange appeared.

“I can—and sometimes do—talk all day long about the safe and efficient operation of a DCD, but unless a person has actually experienced one, they can’t appreciate how truly simple it is to drive,” Brian says. “The video game made my job much easier, providing that first-hand experience the public needed to form an educated opinion."

Observing the drivers also gave the engineering design team some ideas for fine-tuning the design, from modifying curves in a couple spots to avoid lane weaving to improving lane striping for better sight distances.

The team plans on using the 2D/3D/video game progression as a model for upcoming projects that will require some intensive public education and involvement.  But rather than offering these tools as flashy novelties during the design process, the team has been sure to question themselves at every step of the way about the tool’s true applicability and effectiveness as a communication and education tool.

In the case of the interchange, it just made sense; drivers needed to try it out. Roundabouts and other atypical intersections are perfect candidates for this kind of technology. The next step is to further refine this process, introduce it earlier into conceptual design, and refine the product into the most useful format for each stage of the project, whether that’s a video game, a website feature, or an iPad or smart phone app. That way, the opportunity for information sharing and true education about such important public improvements is available to as many users as possible in whatever format works best for them.

A view from the driver’s seat as a video game driver approaches the intersection.