I made brush, right click on it, choose func_wall in drop down list, made it to be solid-no lights, click X to close window, and when I click on that brush it is world ?!? I must say that I have been dealing with VisGroups, maybe that is cause of the problem. I copied that brush into new rmf do the same process, and everything is fine...but in my rmf I can't turn it to func_wall...