3D Scanning for Better BIM: An MEP Firm's Search for an Alternative to Laser ScanningAECbytes Viewpoint #77 (February 11, 2016)
BIM Analyst, Caveo Consulting Engineers
Many architecture, engineering, and construction professionals agree that building information modeling (BIM) champions a new era in project delivery. Leveraging the benefits of BIM involves more than providing a detailed design—it requires dedicated collaboration within the design team and a workflow that works.
My firm, Caveo Consulting Engineers, has provided design and consulting services for the healthcare community for over twelve years. Our dedication to delivering a high quality product that can be utilized by the end user to effectively maintain their facility is paramount. As such, we have committed ourselves not only to implementing BIM effectively, but also to keeping an eye on how we can continue to improve our workflow and produce a higher quality product.
The ability to design and collaborate via a 3D virtual model significantly raises the bar regarding the quality of the deliverable because working in 3D allows team members to optimize designs and address coordination issues before construction begins. However, in order for BIM models to be truly effective, they must be based on accurate designs, which can be challenging to produce solely from record drawings.
Capturing Existing Conditions
In analyzing Caveo’s BIM process, I realized that one of our largest pain points was accurately capturing existing conditions for renovations. Hand drawn notes and surveys only provided us with basic information at the beginning of our design process, and required hours in the field to assess what was actually there. To increase our effectiveness, we needed to start projects with better data and bridge the gaps between the office and the field.
Inputting existing conditions or updating record documents based on pencil and paper documentation (Figure 1) to an accurate 3D model posed a significant challenge, especially when compared to generating the 3D model using a 3D scan to supplement data collected in the field (Figure 2). It was clear that 3D scanning would help us accomplish that but after evaluating many of the major 3D scanning solutions on the market, I began to think that what we needed—something portable with large area coverage—didn’t exist, until I came across an article about Paracosm, a 3D mapping company in Gainesville, Florida.
I contacted Paracosm and signed up as a Beta user to test their 3D scanning tools. Of all the 3D data collection methods we evaluated, Paracosm’s solution turned out to be the best fit for the challenging healthcare environments we work in.
Why We Use Paracosm
Since movement can disrupt scan results, areas must be completely cleared out before using a laser scanner. We work in environments filled with people, often recovering patients, so clearing out an entire floor is not always possible, or requires an excessive amount of coordination to do so. Paracosm’s handheld scanner lets us quickly scan the areas we need, when we need them, without disturbing or relocating occupants. Because it doesn’t require set up, or markers (in most cases), we are able to simply open up the scanning app on our tablets and quickly capture an area without being any more obtrusive than taking notes for a survey. Since we can control what is scanned, we can capture what’s important while omitting areas we don’t really need. Most importantly, if we are working in an active area and need to clear out, we can do it quickly since there’s no setup involved.
Laser scanners do an excellent job capturing fine details, but the resulting files can be so large that they require a powerful computer to work with, and hours in post-processing work to even make use of the data. The point clouds made with Paracosm’s tools are much smaller (~300MB on average), therefore easier to work with and share with other teams.
WorldBuilder, Paracosm’s 3D scanning application, captures depth data from mobile devices. Scanning with a handheld device allows us to fully capture complex pipe systems, mechanical rooms, and even above ceilings—areas that are very difficult to capture using tripod based scanners (Figure 3). Handheld scanning is extremely flexible and allows us to scan over, under, and around objects which results in better coverage.
Cloud Processing for Large Area Coverage
Other smaller handheld units proved more versatile than tripod based scanners but only captured small areas which didn’t benefit us very much. With Paracosm, we can capture everything from single rooms to 5,000 square foot spaces in a single scan. Unlike other handheld scanners on the market that do all of the processing on-device, Paracosm’s 3D reconstruction happens in the cloud so our scanning time is only limited by the battery life of our tablets.
Paracosm’s algorithms can process data captured from multiple devices into a single scan which lets us divide and conquer to scan large areas even faster.
After a few months of evaluating Paracosm’s solution, we decided to fully adopt it and integrate it into our workflow. We started by incorporating 3D scanning into our survey process. Once a space is scanned, we upload the data to Paracosm’s DarkRoom where the data is transformed into fully formed 3D point clouds of the space. Once the models have finished processing, we download them as .rcp files and bring them directly into Autodesk ReCap. We review the point clouds in ReCap, make any necessary edits, and then link them into Revit.
Caveo primarily uses Revit for our BIM process. While AutoCAD is necessary to work with older materials, or materials from other firms, all of our BIM work is done in Revit. Since Paracosm offers the ReCap’s file format, we’re able to bring our point clouds directly into the programs we use without any additional steps.
Stories from the Field
In attempting to route ductwork through a particularly complicated mechanical room in a project, we ran into major communication challenges because a portion of the engineering team, working out of a different office, had to rely on information relayed to them by the survey team.
The site was surveyed twice and thoroughly documented through traditional means, but the room was so complicated that all of the notes, pictures, diagrams, and meetings failed to clearly communicate the multiple coordination issues that made routing the ductwork in this environment so challenging. Once we scanned the space and shared the point cloud with the design team, they were able to fully examine the environment and used the point cloud in Revit (Figure 4) to move electrical panels and accurately route the ductwork. After working with the point cloud, the problem was solved in a day.
On another project, we used both traditional survey methods and 3D scanning to document the layout of several air handling and condensing units serving an indoor pool. While the overall layout could be understood, the routing of the pipes that connected the air handling and condensing units were difficult to understand based on the 2D survey. Scanning allowed us to use the point clouds in Revit to model the racked piping in place, exactly as it was installed in the field.
Virtual Visits Instead of Return Trips
Traditional surveying methods inevitably leave some stones unturned. When a job site is not within close proximity, return trips can increase the overall project cost for the firm. In determining the placement of a new ventilation hood for a pharmacy in a cancer center, we realized that the survey for the chase had not included necessary portions of the electrical system. At first glance, we believed this oversight would require a return trip to collect the missing measurements. Fortunately, a point cloud of the room and the area above the ceiling had been acquired during the survey, and the engineering team was able to use the scan to review the precise location of the proposed chase and verify if portions of the electrical system did lie in its path. The above-ceiling portion of the point cloud saved the engineering team hours of time and provided a quick answer to a relatively simple question that would have taken a significant amount of field work to address otherwise.
Using the scanner to cover entire spaces is extremely useful especially considering that it’s impossible to anticipate which problems or questions will arise over the course of a project. We’ve returned to job sites countless times to provide accurate answers regarding basic issues that required on-site assessment to address. In many cases, scanning has allowed us to bypass the need for return trips because we are able to access the information we need virtually, without leaving our desks.
On another project, we scanned an 8,000 square foot building (Figure 5)—both below and above the ceiling—and brought the entire point cloud into Revit. Thankfully, when a contractor asked questions regarding whether or not specific devices existed in the field, we were able to refer to the scan to provide immediate answers.
Verification and Creation of Record Documents
After working with record drawings long enough, you begin to expect inaccuracies. Poor measurements require a great deal of time to assess and address. 3D scanning streamlines this process considerably. Typically, we rely on scans as powerful tools to help accurately document existing conditions, but we have also discovered that overlaying scans on top of record documents provides a quick means of verifying their validity. While retrofitting the floor of a hospital, for example, a scan was taken of an electrical room to determine if clearances could be maintained for new panel boards (Figure. 6). When we placed the scan into the model, we learned that the dimensions of the room were off. The scan allowed us to adjust our design to ensure that the clearances of the panel boards were maintained based on what was actually in the field.
3D scanning also allows us to create accurate record documents for our clients. One of the first projects we used Paracosm’s technology on involved generating record documents for two boiler replacements and the surrounding areas. After placing the point clouds in Revit, we used them in conjunction with minor notes from the field to completely draw in the piping and ductwork that supported these new boilers exactly as they were installed.
We have found Paracosm’s handheld scanning solution marks, for us, the beginning of a successful bridge between the field and the office. The device is extremely portable, which allows us to capture spaces that would have otherwise been a logistical nightmare, had we been using other methods of scanning. Now that we are able to capture these spaces, we’ve seen effective communication of existing conditions between offices, which has enabled designers working remotely to provide solutions and designs as efficiently as those that are on site. By reducing the number of return trips to the site, we are able to provide faster answers to other members of the team and save multiple hours in travel time alone. Finally, using 3D scanning to verify record documents enables us to catch many things that would have been otherwise overlooked, and creating accurate record documents enables us to deliver a product which the client can rely on to manage their facility.
All of these benefits have inspired us to expand our use of 3D scanning for many of our projects, and we have significantly streamlined our workflow for moving data from the field to the office. As with any new technology, there’s a learning curve, but our team is very enthusiastic about training and expanding the use of scanning here at Caveo. We are extremely driven to continue exploring the many ways in which this new technology increases the quality of our deliverable, enhances our BIM process, and makes our work more about designing and less about logistics.
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