Ah, right, well then!.. Thank you. I use the measure tool a lot, is there a way to preview the design with the kerf adjustment and have visual confirmation of the intended output? I can print all three out as test pieces and get the calliper on them, I just like to see numbers on the screen!
The usual Preview window will do that, although you don’t get any measurement tools:
If you put the original shape and the kerfed shapes on separate layers, then you can measure between them without doing a Preview. Forgetting to disable / delete the layers you don’t want would produce confetti on the platform, though.
The outward kerf gets rounded corners because that’s how the path can stay 5 mm away from the point at the original sharp corners.
I was wrong about the inner kerf: it stays square, because that path is constrained by both sides at the corners. I was visualizing the rounded interior corners left by a cutting tool offset inward from the perimeter, not what you get by tracing that perimeter with the tool center: you can’t make a square hole, but you can make a square post.