I’ve been trying to figure this out all day. I got my part imported from OnShape. It about an eighth inch shorter than my stock. I set the stock offset and limits accordingly so the part is at the bottom of the material.
For the roughing cut Kiri:Moto should clear the top of the part. It doesn’t seem to matter if I have Clear Voids checked or not. I get the same result when slicing or previewing.
One screenshot is with Clear Voids checked, one is without.