Control Point Placement

The following are recommendations for control points placement:

• Distribute control points evenly. Place them more than 5m apart from one another and ideally not in a straight line.

• Place control points at the beginning and end of each scanned dataset.

• Include a minimum of three control points per scanned dataset.

• Place control points in corners, at the ends of corridors. Place one control point at every corner of a long corridor.

• Control points should be placed at least 50 cm from corners. One control point every 25m.

• There is no fixed rule for how many control points to use within a scanned dataset, it all depends on the building layout and use case, but typically placing control points every 25-50m is recommended.

• For low complex halls, it is enough to calculate with 3 control points per 1000 m², while it can go up to 6 control points per 1000 m² for very complex, and fragmented environments in which many small datasets are necessary.

For optimal point cloud precision, we suggest placing control points at intervals of 25 to 30 meters along the route of the device.

Where to put control points in a long corridor

Where to put control points in a large open space

Requirements for NavVis Devices

These requirements describe how to place, label, and verify control points for scanning with NavVis devices. The following requirements ensure alignment accuracy and keep control points visible to the scanning operator.

• To achieve the best possible results in terms of overall accuracy, spread control points across the full planned scanning area.

• Do not add control points in a single straight line, change the height on walls. At least one control point must be offset to the side, not all on a single center line, this ensures a strong geometric profile.

• Control points must use surveyed coordinates that match the survey file IDs written next to the markers.

• Individual control points need:

  • A clear center point

  • A unique ID
    

• Control point identification numbers must use the same number as the one in the Surveyed CP file

• Add control points at:

  • The ends of long runs (e.g. corridors, façades, production lines), and

  • Major transitions (e.g. zone changes, floor changes, geometry changes).

  • Near corners, columns, or other wall breaks / perimeter features.

  • On stable features (e.g. structural columns, permanent walls).

  • At stair landings

  • Near stair and elevator entrances on each level.

  • Zone boundaries, and floor boundaries

  • Near both ends of the corridor or linear run.

  • At mid‑span in long corridors / façades (add more if needed for length/complexity).

  • Place control points at a working height that:

    • Is easy to see from typical scanner positions

    • Is easy to reach for capturing using a NavVis device.

  • Do not place control points in the following:

    • Swinging door areas

    • Tight turning areas.

    • High foot traffic areas where they can be covered (e.g. posters) or damaged.

    • Highly reflective surfaces

    • Walls or floors that have strong patterned backgrounds which reduce visibility.