I was hoping I could figure this one out without the forums, but here I am on the forums again.

I'm trying to make a mold of my mailbox, but I can't seem to find the right one. I want the mold to go on the sides. I was able to make the parting lines. I also made the rectangle for the tooling split. Now why won't the tooling split work? It won't make the two boxes for the molds like it did on my flag. It won't automatically select the core and cavity.