Point Cloud Survey - order

What to ask for when ordering a Point Cloud

Choose UTM or NTM coordinate system for the point cloud survey.

If different scanning companies work in the same project the coordinate system has to be agreed before. This includes if they use GPS devices or the oslo markpunkt

The scanning company should acquire three control points per level in structural elements that are not going to be demolished, so we can ks the point cloud

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❏ An agreement about the project goals, standards and development should be prepared prior to the building survey. The survey team should be aware what is the survey being used for, what are the most important areas to survey and what level of detail is needed.

❏ The level of decimation, file size and data transfer method should also be considered and agreed upon beforehand, and especially when requesting point cloud data.

❏ Areas of intervention should have a point density according to the purpose of its use.

❏ The point cloud model should be segmented into sensible project areas. This means it should be segmented into:

• Interior: by level

• Exterior: by façade (interior and exterior wall face)

  by surroundings

In case of several buildings, the point cloud model should be segmented by building (example in Figure 1)

Figure 1- Point cloud segmentation illustrated by colours

Which allows loading and unloading specific project areas along with their use in the project design. The point cloud model segmentation enhances BIM tools performance.

❏ Point clouds with a lot of noise should be cleaned. This means erasing unwanted points like reflection points from windows and mirrors, too distant data and sometimes cars, people, ongoing works, among others. A cleaned point cloud allows higher output quality and a better visualization and interpretation of the data.

❏ Point cloud model on its own can be insufficient to supply a complete geometric framework for the building survey or to provide information required for the BIMs. The point cloud model should be connected to a survey control framework, and geolocated, for more accurate data. Control will be established by the scanning crew using any coordinate system that the project team requires.

❏ Not all information can be obtained through the point clouds. For this reason, the scanning team should also acquire other kinds of information like field notes, photos or provide 360 photos associated with a 3d model or pdf plans (example in Figure 2).

Figure 2- Example of 3D model or plan associated with 360 photos

❏ The following deliverables will be provided as part of the contract: PTS/PTX , RCS and RCP files