Use the simplify part option before exporting

this should smooth out everything in to nice arcs

go to - database-fittings-pattern switches and tick the simplify part check box

settings for this feature can be changed from the installed machines setup section or from the profile section in Opus

I have never changed these settings but on 2018 version of Cam-Duct the simplify part option seems to have some serious glitches

2017 version works great

hope this helps

1other thing to try is the number of round sections option

this can be changed from database-fittings-pattern options-number of round sections

you can change how many sections it will split a circle in to from here