I apologize if this question has been asked earlier. I am trying to make rounded corner square opening in a cube object of 4:1:0.25 ratio using the boolean feature. It works fine if I use just a standard cube. The opening edges are crisp. But if I use an object from the splin that has a pre-set rounded corners and then use it in the boolean mode, the opening becomes dramaticly distorted. I did the RTFM bit. I could not see anything that would give me a clue. Any suggestions? Thanks