Point clouds from 3D scanning

Tekla Structures
2018
Tekla Structures

Point clouds from 3D scanning

You can now attach point clouds to Tekla Structures models. Point clouds are groups of measured points on the surfaces of objects created with 3D laser scanners, for example, Trimble 3D laser scanners. In construction, the point clouds are mainly used in renovation projects to define the building or structure that is to be renovated. They can also be used to get the exact position of existing machinery, pipework or landscape that need to be taken into consideration on the site. You can also use them for checking execution by importing them as build points into a model to be compared to the design.

When you attach a point cloud to a Tekla Structures model, you can place it either by the model origin or a defined base point.

The original point cloud file is processed and cache files are created in the potree format. The point cloud conversion occurs as a background process, and you can continue working with Tekla Structures meanwhile.

Point cloud data is stored in the folder defined by the advanced option XS_POINT_CLOUD_CACHE_FOLDER. By default, the folder is %LocalAppData%\Trimble\TeklaStructures\PointClouds , for example, C:\Users\<user>\AppData\Local\Trimble\Tekla Structures\PointClouds.This user-specific advanced option is located in the File Locations category in the Advanced Options dialog box. It may be useful to use a network drive for the potree file in a project for sharing purposes. The file will not be copied to the local computer.

If the same point cloud is used in several models, it will not be converted again or duplicated when you attach it. If point clouds are identical, the existing converted file is used, otherwise the file is converted.

In Tekla Structures , point clouds have colors if the original file format supports colors.

Compatible file formats

ASCII ( .asc , .xyz )

E57 ( .e57 )

LAS ( .las )

LAZ ( .laz )

PTS ( .pts )

PTX ( .ptx )

Potree ( .js )

Trimble scan format ( .tzf )

  • To attach a point cloud:

    1. Click thePoint clouds button in the side pane, click Attach , and browse for the point cloud.

    2. Change the scale, if needed.

    3. Select Model origin to place the point cloud in the Tekla Structures model origin, or select a base point to place the point cloud in the real world coordinates.

      If you do not know the coordinate system of the point cloud, select Auto-created base point to get the point cloud near the model origin. This will create an automatic base point with point cloud bounding box min x, min y, and min z coordinates in the Tekla Structures origin.

    4. Click Attach point cloud.

  • To show the point cloud in the model, select the model view where you want to show it, and click the eye buttonnext to the point cloud in the list. When the view is selected, it has a yellow frame.

    When the point cloud is set visible in the model view, you can see the min x, min y, and min z coordinates of the point cloud bounding box on the status bar.

  • To hide the point cloud, click.

  • To detach a point cloud, clickDetach next to the point cloud name in the Point clouds list. Then reopen or save the model.

    Note that you cannot detach a point cloud by pressing Delete on the keyboard.

    The point clouds are cached to the default location or to a location specified by the user. When a point cloud is no longer used in any Tekla Structures model, it is cleaned from the cache.

For more information about point clouds and related limitations, see Point clouds.

Set the default maximum point count in a view

You can use the advanced option XS_SET_MAX_POINT_CLOUD_POINT_COUNT to set the default maximum value for the points in a view. The default value is 10 000 000 (10 million).

This advanced option is system specific, and it is located in the Model View category of the Advanced Options dialog box. Restart Tekla Structures if you change the value.

Clip point clouds and reference models only

Set the user-specific advanced option XS_DO_NOT_CLIP_NATIVE_OBJECTS_WITH_CLIP_PLANE to TRUE to only clip point clouds and reference models with the Clip plane command. Native Tekla Structures objects are not clipped. FALSE is the default value. This advanced option is located in the Model View category in the Advanced Options dialog box.

Redraw the model views after changing the value.

Rendering of point clouds

Point clouds can be seen in both the OpenGL model view and in the DX model view. The DX model view with perspective projection may give a better visual result. Performance with bigger amount of data or a larger number of views may make the DX usage impossible.

Orthogonal projection:

Perspective projection:

Sharing point clouds

Point clouds are normally so large in file size that it is not sensible to share a point cloud as a part of the shared model data. However, there may be a need for multiple persons to use the same point cloud in a project, in which case you can use the point cloud potree file for sharing the point cloud.

You first need to create the potree file and then copy the potree file to a shared location, where other users can get it and attach it to the Tekla Structures model. For more information, see Point clouds in Tekla User Assistance.

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