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852 | ChAPteR 21 Working With Point Clouds

Figure 21.3
Comparing
existing condi-
tions to model
elements

LiDAR can also show you variation to a very fine degree within the scan data in existing
buildings. This can be floors that have variation in the slab, walls that aren’t plumb, slope in
joists, and so on. In Figure 21.4, you can see a LiDAR scan that is using a “heat map” of a floor
slab—the warmer colors indicate points that are closer; the cooler ones represent points that are
farther away. By scanning the floor, we were able to tell that over a couple hundred feet we had
almost 3 inches (75 mm) of variation over the floor. In this project, the point cloud was used to
calculate the amount of fill material needed to bring the floor to a flat, level plane and explain
that cost to the client.

Figure 21.4
lidar shown as a
heat map for floor
deflection

Planning for a LiDAR Survey

Several factors come in to play when trying to plan a laser scan. Planning is an important
part of the process. If planning is done poorly, your scan data may be insufficient or too
detailed, leading to problems when you need to migrate the point cloud into Revit elements.
It’s important to have an understanding of the planning process so that you are able to
communicate the project requirements to the service provider. In this section, we’ll discuss
the basics of preparing for a scan, what to look for, and how to plan for a scan in your
facility.

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