Cutting inside out vs outside in?

I was cutting out a part from 1/4" MDF and didn’t set any supports in Meshcam as I thought they wouldn’t have been needed, but found out the program created the tool path cutting the largest features first, which was a circular perimeter around the part, and then moved to the smaller inner features.

A. Why would the program work from the outside in, forcing you to add support features that otherwise would not be needed and slowing down cutting?

B. Is there a setting that flips this, so it will cut any interior features first and then cuts the features that will remove the part from the rest of the stock?

Mark, MeshCAM was written with monolithic 3D shapes in mind (the samplerhino.stl is a good example). “Flat” 2.5D part cutting is just a byproduct of what MeshCAM can do.

The way to do “cutouts” before “perimeter” is to do two jobs. On the first job, define a Machine Region surrounding the cutouts you want to make. Define the cuts and generate a gcode. Then go back, delete the Machine Region(s) and define a Keepout Region surronding the cutouts you already made. Then generate a second gcode (not changing any other settings) which will just be the perimeter of the part.