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Tip of the Week #15 - Using the Best-Fit Line Command to Draft Catenary Lines

By Joseph Blecha posted 06-23-2017 06:54


Tip #15 - Using Best-Fit Line to Draft Catenary Lines


Did you know you can use the Best-Fit Line to draft catenary power lines in TBC?  This accurate and time-saving tool creates a 3D linestring that can then be used to compute and document minimum clearances, in a Plan Set, or exported in a third-party data format.


Here’s a typical situation:



Station View in TBC - Panorama and Point Cloud data


Powerline and tower data has been collected by a Trimble VISION instrument.  Included in the data are points along the powerline, either through scans and/or Direct Reflex (DR) topo in the field, or Virtual DR in TBC.  


In this example, the powerline data is a part of some SX10 station setup scans.  After refinement with the Classify Regions and Keep In/Keep Out commands to extract the power lines you wish to draft, view the powerlines in 3D View:


Point Cloud only view in 3D


Point Cloud Data after Region Classification, Turning Regions off in View Filter, and using Keep Out to Remove Points


Using the Polygon Select tool, create a selection polygon around one powerline at a time to select each point on the powerline.  Open the Best-Fit Line command in the CAD tab (licensed by the Advanced Drafting module) and match these settings:


Best-fit Line Command and settings


Click OK and repeat for the other two power lines.


Finished 3D Linestrings


Once completed, you’ll have three 3D linestrings for use in your TBC deliverable!


Station View with Power Lines Drafted


Special thanks to Chad Lewis for the data set and workflow suggestion this week!