The Rhino 9 WIP now supports details with boundaries that can be made from any closed curve. This can be done with either the new SetDetailBorder command or by using the FromCurve option in the Detail command.
You can now have layouts with circular “zoomed in” details as shown above.
Not just circles
Any closed curve can be used to define a detail’s boundary
DWG file support
Non-rectangular details can be imported from existing dwg files. Exporting non-rectangular details to dwg is also supported.
Please try it out and let us know what needs to be done to improve this feature.