if i write an app on Unity3d 3.5 for OSX (finished), can i export it for Windows users or i have to re-write it on Windows?, not a web player it is a full app, high end 3d and use of data bases (most in universal formats or internal created).
Unless you hard-coded something OS-X specific (like file paths), then it will work on Windows. That’s sort of the point of Unity’s publishing options…there wouldn’t really be any reason for the Windows publishing option to exist in the OS X version of Unity if you had to re-write everything.