Import and Process Measured Data

We import measured physical data for tunnels to application layers. If the data file contains more than 10,000 points, we will be asked whether to import the points to a point cloud object. We use point cloud objects for large point sets to increase performance in the program.

The program can read scan data formats LAS and Leica pts. Alternatively, we can set up a user-defined format, i.e., a general ASCII format with X, Y, and Z coordinates. We adapt this format in the export options of the processing program for the scan data.

A dedicated template for tunnel data has been created, Innmålt_tunnel.al_. The template contains pre-configured layer setup as well as the special presentation rule point cloud for better handling of large data sets.

Layer numbers 91-95 are reserved for tunnel data.

Layer 91 for tunnel data

Filter and Edit Data

The point cloud should ideally be fully edited before import, but we have some functions to edit, extract, and filter/remove data. We find these functions on the context menu when line and point cloud objects are selected on the screen.

Extract Points Along Line

If the point cloud in the application layer is larger than needed, you can extract data from it to get more manageable data sets. This creates a new point cloud object with fewer data points.

Point cloud 2 with more manageable data sets.

This function has four different methods for extracting data. You can read more about the methods in the dialog help. Note also that bulge detection is a suitable application area for this function. The result in this case is a separate point cloud object for the points that lie within a given layer, for example, the blasting contour.

Edit Point Cloud Along Line

This is ideal for editing noise that should not be included in the triangulation, including:

• Pipes, signs, fans, and more inside the tunnel
• Points outside the tunnel portal, or other objects to be removed

This function can also be used to check the scan.

Remove Points Along Line

This function can be useful for removing points (typically noise) outside a given buffer zone. It requires that we have a theoretical layer, for example tunnel blasting contour.

Clean Up Triangles and Point Clouds

We can use this function to reduce the number of triangles in triangle nets and the number of points in point clouds. The function is based only on a geometric consideration of proximity. It takes no special consideration of edge zones or sharp breaks in the data. The routine finds the nearest points within minimum point distance and calculates the average value for these (x, y, z).

Triangulate Point Clouds

The program has 2 methods that can be used to triangulate a tunnel scan: a true 3D triangulation and a 2D triangulation with extra conditions. The latter function requires that we have a line to triangulate the points/point cloud object against. It can be used both for selections of point objects and for a point cloud object with many points.

Triangulate Points Against Line

Procedure

1. Create new application layer
2. Import data to application layer (point cloud object)
3. Define the application layer as a layer, layer types 91-95 are reserved for tunnel
4. Optionally extract data so that we get a more manageable point cloud object
5. Mark point cloud object and line definition in SFI model
6. Select Triangulate points against line... from the context menu

Application layers are described in more detail in the section Application Layers.

Note

In profile generation, you can enter Parameters for triangulation.
Parameters for triangulation are used to set up parameters for generating profiles through point clouds. You can find it in the dialogs for profile generation. It is then not necessary to triangulate the point cloud in advance.