Viewing Point Clouds with Scan-Based Sampling in Trimble RealWorks

Working with scan datasets requires numerous tools, tips, and tricks to create finalized productions. One valuable tool to assist you in your workflows is Trimble^® RealWorks^TM Scan-Based Sampling.

Scan-Based Sampling can be found within the Sampling tool located in the Production mode, under the Edit tab, and in the Cloud section of the ribbon. Select the dropdown arrow, choose Scan-Based Sampling, select the Split per Station box, and hit Create. 

Now a folder containing each individual scan station will appear within the lower WorkSpace window, below your Project Cloud. Each scan is viewable with the lightbulb icon and assigned an individualized station color. Each scan can now be selected and displayed separate from the remaining project. 

Let’s go over a few applications of this tool:

One use for Scan-Based Sampling is single or specific scan segmentation. Unwanted data is sometimes present in a single scan and isolating this scan can make cleaning easier. For example, the diligent employee responding to an urgent email from the CEO can quickly be segmented from the station scan. The single scan is orientated to avoid selecting any background points, and the segmentation is quickly made.

Scan-Based Sampling can also be combined with other tools. 

Here are some of my favorites:

• The measure tool for dimensioning surfaces, where working with a single scan ensures background points are not selected. This tool can be found on many of the Production ribbon tabs, including Home, Drawing, and Model.

• The magnifier tool can be used for quick inspection of cloud alignment. To activate this tool, press the n button on the keyboard while the cursor is hovering over the area of interest. For more information on the magnifier tool, check out this previous Scanning Tip of the Month. 

• And the limit box tool is still available to narrow in on the most specific portions of your point cloud. This tool can be found in the View tab of the ribbon.  In the example below, I am only viewing 3 station scans from my point cloud.

Once satisfied with your segmentation edits, you can combine the individual scans back into a single cloud object by selecting the segmented scans, right clicking the mouse, and clicking merge. This version can then be used with mesh creation, modeling, or inspection tools as you normally would. As an alternative you can also use these tools for the individual scans.

One additional application of using the Scan-Based Sampling tool is registration inspection during production processes. The series of images below show some registration errors that were found while segmenting. The station colors provided by the Station-Based Sampling made the misalignment of the road more distinct.

A closer look shows three distinct layers, demonstrating the registration issue.

Using the Scan-Based Sampling tool allows the problem scans to be identified for registration refinement by dimming each scan until the culprits are found. In this case, scans 2, 10, and 11 as shown below.

Let us know what other uses you found for Scan-Based Sampling and how it affected your workflows. Until next time, keep on scanning.

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