Hi Vince,
If you’re looking for G3 transitions, you might want to try byRhinoGadget, which has a variety of corner options.
First, FilletSmooth lets you create corner curves with G2 or higher continuity. A recent update also added Match curve G3, so that may be worth a look as well.
byRhinoGadget is a free plugin. You can install it from the PackageManager in Rhino or from Food4Rhino:
- Food4Rhino: byRhinoGadget | Food4Rhino
- Help (English): byRhinoGadget - byRhinoGadget
Hope this helps!