Miscommunication among construction teams about what has been done and the materials used can result in project delays and cost overruns. But now, thanks to augmented reality, a variety of helpful activities—including seeing the up-to-the minute status of construction, virtual walk-throughs around a site, and faster access to documents like floor plans and schedules—can be brought to handheld devices on the construction site.
Augmented reality (AR) applications present a composite view of the real world on a display that superimposes computer-generated images. AR is now common in a number of industries, including construction. By downloading an AR app to a smartphone or tablet, users can scroll around a site to view 3-D images of, say, different sections of a building as it is being built and what it will look like once it’s completed. Some apps store such documents as floor plans, project specifications, status of projects, and changes made to the original plans, providing fast access to them.
“It can sometimes take hours to address a question on the job site itself, mainly because of a lack of access to the information that’s needed,” says Mani Golparvar-Fard, an assistant professor of civil and environmental and computer engineering, and a faculty fellow of the National Center for Super Computing Applications, both at the University of Illinois, in Urbana-Champaign. He spoke at the Urban Augmented Reality webinar held on 8 May sponsored by the IEEE Standards Association. “Augmented reality applications can cut the access problem down to less than a minute, saving developers, contractors, and ultimately clients time and money, while helping improve communications among the site personnel.”
Golparvar-Fard is currently developing ConstructAide, an AR app for home and large-building construction sites that will present the ability to not only visualize projects in 3-D—in the past, present, and future—but also interact with underlying 3-D architectural and construction models. Users can modify the project model in minute detail and view it from multiple viewpoints at any stage of construction. This would allow designs and layouts to be changed more easily than ever and for projects to be reviewed faster and in more detail.
He is working on ConstructAide with IEEE Graduate Student Member Kevin Karsch, a Ph.D. candidate at the University of Illinois and a predoctoral fellow of the National Science Foundation, along with IEEE Fellow David Forsyth, a professor of computer science at the school. Golparvar-Fard received initial funding from the National Science Foundation. A working prototype is expected to be ready by December.
Golparvar-Fard’s ConstructAide isn’t the only builder’s app, however. Several are already on the market.
Apps like SmartReality can make 2-D blueprints appear as 3-D models when a mobile device with a camera is placed so as to read the print. This helps visualize what the project will look like once it’s completed. Other construction-site apps are also built around a smart device: When you point it at a building in progress, it can display virtual images of what the space will ultimately look like.
Many of these apps require Quick Response codes, a standard industry bar code readable by a smart device that holds identifying information about the item to which it’s attached. These are often seen in retail stores, when a customer can scan the code with a smartphone to learn more about a product. In construction, QR codes are placed around a site, mainly on already completed doorposts. The cost of these apps and their services depends on factors such as the square footage of a project and the number of its documents and photographs.
The next step, however, is for QR codes to disappear. They would be replaced by techniques such as image-recognition and computer vision, in which photos taken at the construction site would help build a lifelike model of a completed project. This is what ConstructAide is expected to accomplish.
Working from blueprints, mock-ups, and construction models, ConstructAide initially will form a realistic 3-D rendering of the final plan. Then, as construction progresses, the system will process photos submitted from a smartphone or tablet anywhere on the construction site. It will use a model-assisted “structure-from-motion” formulation, a variant of a technique that recognizes 3-D structures from 2-D images, coupled with information already in the device pegging its location on the site. Whenever a new photo is taken, ConstructAide will latch that image automatically to the part of the 3-D model with which it is associated.
Unlike other systems that require GPS information on the smart device or markers to find the user’s location, ConstructAide relies on the content of the image—what it looks like—to identify the location as well as the orientation of the device. This also helps to discriminate among shapes that are photographed, such as telling the difference between a door and a window.
The app also will incorporate points of occlusion, which refers to parts of an image not visible from certain viewpoints. This will make it easy to see parts of the model that would otherwise be hidden from the viewer.
To take full advantage of ConstructAide, a construction crew would have to take photos at every stage of the project—something that’s already being done on many large projects—and upload them to the app. Some projects hire photographers to do this from companies like Multivista, Job Site Visitor, and EarthCam. Once they’re uploaded, the images are organized and stored, along with the construction plans and final models, in a cloud-based server.
ConstructAide will further allow users to navigate around the multidimensional models in a Photoshop-like way that will help them to select specific elements from photographs, hide or show them in a virtual image, or even alter them. Moreover, Golparvar-Fard likens his app to 4-D, or 3-D plus the element of time. Once a change is made from one user’s smartphone, all other users can view it immediately on their own devices and respond to it or change what they’re doing based on that latest version. It can also provide an “X-ray” into the past. For example, if managers must check on what is actually behind the drywall, or the type of flooring laid under the carpeting, they can review the construction history of any part of the building.
AR apps can also help in the sale of a home. Several can inform would-be buyers of properties for sale as they drive through a neighborhood, and which may be available to view for open house. The apps also offer access to floor plans, virtual tours, and other information.
Some of these real estate apps can handle a huge number of properties. HomeFinder, for example, combines GPS information from users’ smartphones with real estate listings from more than 130 newspapers to notify users when they pass one of its 3.5 million listings. Users can then scan a property with their smartphones to gain more information. Similar apps include HomeSpotter, MARS app, and Virtual View as well as HomeSnap, which offer the added feature of outlining property boundaries in the image.
It’s possible to view the smallest details, such as the flooring construction or what a room might look like with furniture—features to be added to ConstructAide, as well.
“We don’t want prospective home owners to wait until everything is finished,” Golparvar-Fard says. “We want them to walk into a building that is still under construction and see how their choices on the interior finishes fit in with the rest of the building. The availability of personal smart devices has opened the door for augmented reality, which will help smooth the way when it comes to building and selling real estate.”