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TBC Does That: Draft Catenary Lines with Best-Fit Line Command

What TBC does

In cold weather, power lines contract and in hot weather they sag. The power industry must analyze the shape of catenary lines to ensure clearances are adequate regardless of the weather. In TBC, the Best-fit Line command automates the process of drafting catenary power lines in point cloud data. Algorithms accurately create 3D linestrings by calculating the natural curve of a line between towers.

Why this helps you

By automating the process to draft a catenary curve, less time is required to model power lines in 3D. By replacing manual digitizing with a mathematical calculation, accuracy is improved, which is particularly important to maintain public safety and compliance regarding minimum clearances above roads and railroad tracks .

How it works

Starting with a point cloud file, use the Polygon Select tool to pick points along the power line. (Pro tip: the Cutting Plane View is a great help to filter out irrelevant points.)

By clicking on the Best-fit Line command in the CAD tab and choose Polynomial Curve 3D as the line type, a catenary line is generated for that set of points. Repeat for each individual power line, and use the generated linestrings to compute and document clearances.

For more details about using TBC to draft catenary lines, go to TBC Tip of the Week 15


The “TBC Does That” series, written by the Trimble Business Center (TBC) Team, focuses on the broad range of functionality that TBC delivers to you. Periodically we will release information to help you improve productivity by making the most of TBC’s built-in tools.