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This plugin intends to enable direct generation of toolpaths from physical line following. This is illustrated in this.

This could be useful in cases where the object is not originating from a CAD drawing, but is coming from a physical object, like cutting a piece to fit into an existing odd-shaped hole.

This has only been tested on OctoPi. It has only been tested with the latest version of OctoPrint. It might work on earlier versions based on Python 3, but the odds are low that it would work on Python 2.

The plugin depends on other Python packages but does not depend on binary applications, so it might work on Windows or Ubuntu x86 hosts. These have not been tested.

Installation on a Raspberry Pi running OctoPi should work through the plugin manager without any extra steps. Installation does take some time (approximately 10 minutes) to build numpy. (The plugin also uses OpenCV, but the dependency is automatically resolved with precompiled binaries so it does not take a lot of extra time. Only numpy has to be built.) Building numpy only takes time on the first installation. If the plugin is uninstalled and reinstalled, it is much quicker.

The scan requires a physical printout of the “board96.png” image. This should be printed at 96 DPI. The target should be cut so the paper extends about 2mm beyond the head of the arrow. The arrow should be placed so that the line is about 10mm in front of the head of the arrow.

The line follower requires that the line to be traced is a single closed curve with no intersections (i.e. no figure 8) and with no gaps in the line. Currently the line follower is not robust to different line widths or colors, so trial and error might be necessary to find a line width that works well. The line follower is also not robust to background clutter (e.g. wood grain) so for best odds of success, the workpiece should be a relatively uniform, light color.

Manually jog the tool so that the arrow head is near the center of the field of view.”

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