The dialog box for the extension and the options available to remove duplicate line segements. NB4: All shape elements have to be converted to path, else they will be ignored (you will get a warning). NB3: The extension ignores grouped paths. This is because the average of each pair of controlpoints replace the original controlpoints i.e. NB2: Interpolation might cause a rough or slight deformation compared to the original paths. NB: If the tolerance is larger than the length of the some line segments and the option to include matches where a path is overlapping itself might cause finding a match between neighboring small segments. Optionally interpolate the remaining line segment with the removed line segment.Using snapping will most often cause some discrepancy. What looks like a exact match will often be slightly different when regarding all decimals. Adding a tolerance to allow for some discrepancies and still regard it a match.Include searching for matching segments where one continuous path is overlapping itself.There are three additional options to select: Identical line segments will always be removed, that is when all four control points are the exact same independent of direction (a reversed match is also a match). All four control points of the cubic bezier curves are compared after converting the paths to cubic super path. The extension compare all line segments (between nodes). (Scroll down to bottom of this post to find the download links). So I wanted to give it a try and write that extension.

Others have provided Inkscape extensions to remove duplicate lines, but so far I’ve not found any that accept a user defined tolerance for the matching of segments allowing for inaccuracies f.x. This might be problematic as the cutter will trace that path twize and might mess up the product or, if used as a plotter, spill the ink.

Sometimes there might be duplicate line segments. I recentIy published an Inkscape extension to remove duplicate nodes that is useful when preparing designs for my cutting machine.

Inkscape text to path extension