Drain holes are boleean operation,xhy not add more shape from user (trapeizoid,square …)
I am modeler and use assembly key for model with simple shape .
Another use of custom drain holes :we can stamp parts with an hole number easely identify parts
Add more drain hole pattern
sylus
#1
formware
#2
Stamping and adding letters are on the list.
The drainage holes now are booleaned when you slice to 2d slices.
This is on purpose; since the actual boolean in 3d can lead to problems and strange results.