Drag and drop your 3mf into Cura. Then after it a lot it would possibly not glance slightly proper, however the items shall be there. Then export it as a 3mf the use of the menus in Cura. Then open it in 3d builder once more and run a restore on it if the discussion comes up. Then wait a very long time and do a contemporary save beneath a brand new identify when it’s finished.
If the style continues to be open in 3d builder then you’ll reserve it as an object document after which reload it from the item document after which reserve it as 3mf beneath a brand new identify and stay operating on it.
You’ll steer clear of 3dbuilder shitting the mattress as frequently by means of replica and pasting gadgets or small teams of gadgets that you need to paintings on into a brand new scene then doing all your paintings there and when finished replica and pasting it again into the total scene to interchange the phase that you just copied to switch.