Parameterized flanged lens hood

The last hood I made for this lens ( http://www.thingiverse.com/thing:181866 ) kept falling off so this is version 2 with lugs.
This is a customisable lens hood which generates three lugs at the base to lock the hood in place.
This is the fitting for my Olympus 75-300mm zoom lens, other makes probably use the same size.