Moi delete face after boolean Union.

 From:  Jack Lee (JACKLEEINST) 19 Mar 2021  (1 of 9) 
10237.1 
I'm learning this tutorial.

http://moi3d.com/forum/messages.php?webtag=MOI&msg=6706.1


after done the Boolean Union, moi delete one face, but it still solid. very strange