Ah, I have it figured out now. You see, I wanted a grate on the door that could be shot through, like the one in office complex that leads to the room where the scientist gets pulled into the vent. The one with the television? Anyway, I found out that you can't shoot through that grate. I guess you can't make a clip brush that rotates with the door after all. Yes, I know all about origin brushed, however. Welp, I guess that's it. Thanks for your help!