Prints with holes

[Roxy]

I have had reasonable success adding the nozzle diameter to any internal hole radii. So, for a 10mm diameter internal hole printed with a 0.4mm nozzle I would create a hole 10.8mm wide, thats a radius of 5mm plus 0.4mm for the nozzle.
Not an exact art but often very close.

If this rule of thumb works on a lot of printers... It will be worth high lighting it! Next time I'm doing holes, I'm going to check this out.