thanks fedex for your answer.

its a three-store building with many rooms. some rooms are empty and not seen, not used. but i can't delete them, since their walls are in the same time walls of other rooms. the question is shall i leave them empty as they are or fill them with brushes?

I did the optimization myself since noone helped :-)
(maybe its better that way)

but i have one question left
what do you do for big&empty&unused rooms to get the best performance?

just leave them empty without doing nothing?
fill them with brushes wholely?
use hint/skip/null textures?

i am waiting for a short answer.
thanks.

Dear Participants,

I am new at this and tried to make a map which isn't so big. But i don't know how to optimize it. Can someone download, revise and send back? Thanks in advance.

To download:
http://rapidshare.com/files/280801855/70_deneme.rmf.html