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The field scanning process: How to get the best results

Once your laser scan has been ordered, there are some things you can do to prepare for our crews.

First, prior to the scan, have someone (preferably a knowledgeable project manager) onsite to communicate with the scan team when they arrive.

Make sure your plant managers know crews are coming. If there is a local safety course that needs to completed or specific plant instructions, let them know upfront. Also let crews know if there is special gear they may need like moon suits, hairnets, safety glasses or ear protection.

The project walk-through is a very valuable process because this is where we determine the location of the scanner setups.

Let crews know what is most important and what is less important. If a major conduit with fiber optics, a power transmission conduit, or particular piece of machinery is important to your project, for example, it is important to let the scanning crew know.

Also make sure the scanning crew has a contact that they can call if they have questions or need clarification mid-scan.

Crews will place targets around the scan area to tie all of the scans together and will remove them upon completion of the site visit. Once they understand the limits and the prime areas of interest, the scanning process will begin.

Though it is great to watch them work, these teams are professional and the less direction they have, the better the results! A typical job can take two days to several weeks. Each night, scanned data for the day will be checked to make sure there are no gaps or geometric issues with the data.

For black and white scan data, the process is simply this: scan, move to a new location, scan, move to a new location, etc. For color data, a set of photographs is added to the process: scan, remove the scanner, add a camera, take seven photographs (six at 60-degrees horizontally, one straight up), move the scanner, take photos at the new location, replace the camera with the scanner, scan, and repeat this sequence throughout the site.

This allows our crews to produce high-quality TrueView files. When they get into a rhythm, the above sequence maximizes efficiency up to 100%.

Post Processing

When the scan data comes back into the office, data is exported from the crew’s field laptop to the desktop. On large jobs, this will take several hours.

Next, if there are color photos, the color photo data is downloaded and registered to the point cloud. This process can take 5-10 minutes per set up. Around 100 set-ups can take 15 hours of technician time. (If there is only black & white data, we skip this step.)

Once the photo data is added to the raw data, the target information is then added to the data set. The data is then run through the final registration process. This program compares the data set to all the other common data sets and produces the final registered point cloud.

The point cloud is then tested visually and geometrically to make sure there are no errors. This is done by cutting it like a wedding cake to see that all of the horizontal surfaces line up and also looking at elevation views and pipe runs to make sure that these are consistent throughout the cloud.

After these are tested, the final registered point cloud is ready to be used. Files are then loaded on to a hard drive and shipped to you, the customer!

Now that you have the point cloud data, what do you do with it?

Registered point cloud data can be exported into AutoCAD, MicroStation, Bentley, Revit, Autodesk Recap and many other computer programs. Designers can then take this data and design and model it in a 3D environment.

A TrueView map of the site showing 3D spherical data in black & white or color can be created. You can measure between points in the point cloud with this free program.

Warning: We always recommend that for precise measurements, you use the point cloud information and not TrueView. The angle of the view can affect the measured distance in TrueView. At a minimum, check the measurement from several different views.

Computer models can also be built in Revit, AutoCAD or MicroStation and delivered to the client. These models can be imported into the point cloud and then “clashed” to see if the new model interferes with the existing point cloud.

Want to learn more? Contact us today to learn if a laser scan is right for your next project.

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Tate Jones has over 40 years of experience in land and aerial surveying and was one of the country’s earliest adopters of 3D laser scanning technology. A nationally recognized expert in the field of 3D data capture, he has worked with hundreds of clients in the engineering, architectural and construction industries. Contact him at tjones@lasurveying.com or visit www.landairsurveying.com.

 

3D Laser Scanning: The New Industry Standard

When we first started laser scanning back in 2005, we replaced some of our total station surveying equipment with scanning technology. As much as anything, this was a great way for us to learn how to use the technology and understand its capabilities and limitations.

Early on, much of the work we did involved transportation projects and large complicated intersection surveys. There were many immediate benefits. For one, our surveyors were no longer put out into traffic and in harm’s way.

Another benefit was that we didn’t have to drive across town or across the state just to check on a few ambiguous points in a survey. Instead, we could just go back and look at the point cloud.

Today, in 2012, the entire world of architectural and engineering design and construction has changed. While before we had to convince clients of the benefits of using laser surveys, we now have a growing client base that simply will not consider starting a project without one.

In addition to providing accurate spatial information to civil engineers, plant designers, architects, contractors – and even insurance companies and crime scene investigators – laser scanning saves both time and money.

The truth is that in very complicated environments – like a mechanical heating and air conditioning plant room or a baggage room in an airport – the cost of scanning is nominal when compared to the total cost of the project.

Here are four primary reasons 3D laser surveys, or high-definition scanning, is quickly becoming the new industry standard when it comes to making precise measurements in complicated environments:

Reason #1: Scanner Speed

The speed of scanning has changed dramatically compared to what it was just seven years ago.

The first scanner we purchased (and still use today) took one hour for a 360-degree spherical orbit. Today, with our current scanners, it takes just six minutes.  This speed enables us to take many more scan set-ups than we used to take.

With our phase-based high speed scanner, we can now get 40 to 60 scans per day, which is very adequate to cover a large two-story mechanical room. To get the same amount of scans seven years ago would have taken a week.

In areas like these, it is the detail we look for, not the range. In extremely complicated areas, we make a set of scans on all sides. This data is invaluable to designers because it allows them to avoid interferences that often occur in these types of areas.

Reason #2: Software Improvements

Improved software programming has also contributed to the widespread acceptance of scanning technology.

I remember talking to clients back in 2005 and our message was something like this, “We will scan for you, then give you a 2D deliverable set of drawings that you can use to design your project.” When they would ask if they could use the point cloud in their design, our answer was always the same: “Yes, but you will have to buy $10,000 worth of software.”

As you can probably imagine, this was not an easy sell.

Fortunately, today Bentley, AutoCAD and Revit all have point cloud engines in them. The difference between an engine and a viewer is that we can now load a point cloud into an “engine” for a client and they can use the data in the design without having to purchase expensive “point cloud” software.

In fact, one of the takeaways from a scanning conference I recently attended was that all of the major software providers are moving to full 3D software design systems. They finally understand what we have known for years. Why would you survey in 3D, flatten the data to 2D, design in 2D then build in 3D? It just doesn’t make sense.

Reason #3: Clash Detection

This alone is worth the cost of a 3D laser survey.

Consider that if a project is modeled in the design phase, the completed final design – including the MEP systems, air handling systems, structural system and all of the architectural design – can be placed within the point cloud and clash detected. Anything that interferes with another system can be seen immediately and corrected before construction.

This is huge! What prudent engineer, designer or contractor would not want this advantage?  How important would this be to an owner?

Reason #4: TrueView or 360-Degree Spherical Photography

This technology has also improved quite a bit in the last seven years. When we first started scanning, we were fascinated with the fact that scanners could take photographs of the surrounding area, and then take that photographic data and overlay it with the scan data to make general measurements to the environment.

Unfortunately, back then the on-board camera was not as good as we had hoped and sometimes the pictures would come out octagonal and disjointed. As the process became more refined, we were able to mount a high resolution camera on the scanner and produce a crystal clear, color spherical photograph of the site.

This is a big step because it allows you to view a site from any scan set up. You can add text and information to the photographs and then e-mail a specific view to a client across the country or across the world. (In this case, some of our clients pay for our scanning fees with their savings in plane tickets!) This tool also enables clients to look out from the center of every scan and saves lots of time and discussion as to what is or is not located in the area of interest.

High definition scanning has quickly evolved from an emerging technology to an industry best practice when it comes to complicated projects. The construction process always includes many unknowns and the chance of design and construction errors is always high.

Why put yourself in the position of having to explain how a construction project was slowed down or over-budget because a laser scan was not the foundation of the project?

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Tate Jones has over 40 years of experience in land and aerial surveying and was one of the country’s earliest adopters of 3D laser scanning technology. A nationally recognized expert in the field of 3D data capture, he has worked with hundreds of clients in the engineering, architectural and construction industries. Contact him at tjones@lasurveying.com,  tjones@3DLaserSurveys.com or visit www.3DLaserSurveys.com.