I suggest to use Cura 15.04.6, there you just right-click an object, choose "Multiply object" from the menu and enter how many objects you want.
Cura 2.1.2 still seems to be in some pre-alpa state, it's slow and buggy and lacks many features of the original Cura (versions 15.04.6 and older).
Recommended Posts
DaHai8 74
You could make 3 duplicates in a row or column (for 4 total), group them and then duplicate the group 4 times (4 x 5 = 20).
That's the only way I know to do it at this point.
Link to post
Share on other sites