(by cesarvandevelde)
RhinoGears is a plugin that can be used to generate custom gears, including involute gears, racks, bevel gears and helical gears.
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RhinoGears is a plugin for Rhinoceros that can be used to generate custom gears. This script is partially based on GearGen by Thomas Anagnostou. However, the original GearGen is incompatible with Rhino for Mac. RhinoGears is written in Python and is compatible with both Windows and Mac versions of Rhino 5. This plugin is open source, source code is available at https://github.com/cesarvandevelde/rhino-gears. Contributions are welcome!


After installation, the following commands will be available:

  • InvoluteGear — Generate a gear curve with an involute gear tooth profile. Optionally also outputs the gear's pitch circle.
  • Rack — Generate a rack curve for a rack and pinion system.
  • BevelGearSrf — Generate a bevel (conical) gear surface with a specific cone angle. Optionally outputs the gear's pitch cone surface.
  • HelicalGearSrf — Generate a helical gear surface with a specific helix angle. Optionally outputs the gear's pitch cylinder surface.

Known issue — "Unknown Command" (Windows)

In some cases, Rhino will not recognize the new commands provided by RhinoGears, even though the plugin is installed correctly. This happens because Rhino failed to load the Python scripting environment automatically. This is a confirmed bug in Rhino for Windows (described here).

To work around this issue, enter the command `EditPythonScript` and close the window that pops up. The plugin commands should now work.

General hints

  1. Gears that mesh correctly have the same module and the same pressure angle. In addition, their pitch circles should be tangential to one another.
  2. The module of a gear determines its overall size. The diameter of a gear's pitch circle is equal to the module times the number of teeth.
  3. The pressure angle determines the shape of the gear tooth. A higher pressure angle leads to stronger, noisier gear teeth. Standard values are 14.5, 20 and 25 degrees.