Magicmerly

Thanky you Greg, I didn't know about the red part I have learn not one but two things today, thank you 🙂

and this is the model 16 hole half round 6.6mm dia holes (10mm thick).stl

Sorry this is what I'm trying to slice CE3_16 hole half round 6.6mm dia holes (10mm thick).3mf

I have an STL with 6.6mm holes in (see pic) when I slice it for my ender 3, the holes get filled in (despite me not telling Cura to do that) I've printed earlier variants of this with larger holes in with no problem, so not sure why Cura is filling in the holes now, please advise.