text: First of all,actors do have to go to castings...We usually think that just because they are already famous or well known, they always get called for parts. that is far from the truth..\nSome screen writers make characters having a specific actor in mind, like for example Tarantino that usually wants an actor in specific...but most of the time..managers get the screenplay(movie) and contact there actor and make them do the casting for that part.some actors get it..some dont...you can be a great actor but if another one makes the role of a "retard" just a little bit better that you,then you know who will most likely win the part.