Once loaded, the SPI command can be used to create patterns, first by defining the outer circle of the pattern: Select the center point: Radius of the outer circle: Then the inner circle which "rolls" around the outer circle: Radius of the smaller circle: Followed by the distance of the pen from the center of this smaller circle: Pen distance from the center of the smaller circle: The values you use will be remembered to show a preview of this shape when you create your next pattern. The "resolution" of the polyline generated for a spiro is set as "1" while drawing temporary patterns during a jig and "10" for the final, perfected spiro. These default values can be adjusted using the SPISEGS command, which will prompt for each value, in turn: Enter segment resolution for jigged spiro: Enter segment resolution for perfected spiro: These values will not be saved anywhere, and so will return to their default values during each subsequent editing session.

The installer that ran when you downloaded this app from Autodesk App Store will start installing the app. Or, double-click the downloaded installer to install the app. You may need to restart the Autodesk product to be able to run the app.

To uninstall this app, exit the Autodesk product if you are currently running it.

On Windows 11 and 10 version 1703 or later press Windows+I on the keyboard to access Settings or click or right-click the Windows Start button and then select Settings. Click on Apps (optionally followed by Apps & Features). On older Windows versions click Control Panel > Programs > Programs and Features or Control Panel > Add.

The app was originally published as an ADN Plugin of the Month. See also our app page.