Something common to hotwire cutters:
1. It is complicated to cut an inner hole without leaving an enter/exit path.
2. CAM software rarely understands that there is no "safe Z" for rapids.

How about solving that problem by using a 1mm diameter "hot pin" that is supported only from one side? With a solenoid to retract the pin to a "safe z", you could allow the cam software to use rapids carelessly and cut interior shapes.

What I propose might only be applicable to the type of 2-axis foam cutter I built.

What do you guys think? Is it feasible? How small of a diameter pin could I get away with? 1mm? 0.5mm if moving really slowly?