Unrolling
Function Description: Unrolls the tunnel point cloud along the centerline into a planar point cloud in the (Mileage, Arc Length, Depth) coordinate system. The intensity, color, and other attribute information from the source point cloud will be retained in the results.
Projection Coordinate System
The projection coordinate system consists of three dimensions: Mileage, Arc Length, and Depth:
Mileage: The mileage value of the centerline corresponding to the unrolled point.
Arc Length: The arc length value corresponding to the projection onto the standard contour, starting from the Start Azimuth, with clockwise as positive.
Depth: The difference between the actual contour point radius and the projected point radius when projected onto the standard contour (radius is the distance from the point to the centerline point).
Parameters
Source Class: Tunnel point cloud class.
Projection Method: Supports two methods: Segmented Projection and Cylindrical Projection.
Segmented Projection: Projects tunnel points onto the nearest defined segment.
Cylindrical Projection: Projects tunnel points onto a cylinder with the centerline as the axis and a fixed radius.
Projection Segment: The current segment participating in projection, used for Segmented Projection mode.
Radius: Projection cylinder radius, used for Cylindrical Projection mode.
Output Directory: Result output path.
Note: The output considers chain break definitions. Non-continuous mileage intervals are output to different files; if no chain break is defined, output to the same file.
Start Azimuth: Defines the starting position for contour unrolling (for azimuth definition, see Centerline Extraction). The default is 0°, which is the zenith direction. After unrolling, points at the zenith direction have an arc length of 0.
Max Distance: Controls the point selection range. Points within the Max Distance range from the tunnel centerline are taken to participate in calculation.
Steps
Click Unrolling to activate the function;
Set the Projection Method. When selecting Segmented Projection, you need to select the Projection Segment; when selecting Cylindrical Projection, you need to set the Radius;
Set other parameters as needed;
Click OK to execute the tunnel point cloud unrolling.
