I want to make a hollow part that will also have 2 apertures.  I will be using a manual wet lay up.   I’m designing the pattern in Fusion 360 and I’m wondering whether it would be a good idea to somehow mark on the pattern (say with an “engraved” line) where the apertures need to be?  It seems to me this would help in blanking off the apertures when making the mould.
What is best practice for this type of thing?

Slight lines marked on the pattern work well.  Or you can make cutting templates to use afterwards to cut the apertures.  There is no set way, whatever works best for you. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant