what is the function of stage design

Paintings and statues are judged by eye. If they are beautiful,most people will dmire them.This is not true of design for a stage. 

In many cases, a picture of shadow box might make a pleasant wall decoration if it were attractively painted. However, it would be a very limited set for a play.

There are even times when beauty can spoil a stage design. A scene laid in the home of a woman noted for her poor taste could not afford to be beautiful. It would miss the whole point of the play. Also, comedies cease to be funny if the background is too beautiful. 

I learned this the hard way when I staged a fast, wise-cracking comedy and let my designer provide a lovely set in soft tones of pink and blue. An audience looking at such a scene is no more inclined to laugh than a congregation in a church would be.

Although a stage designer need not always aim at beauty as most artists do, his designs are expected to meet practical requirements that the artist rarely has to face. 

A sting must suit the play. It should create the strongest possible effect with the leas effort and expense. It is worthless if it fails to fit the stage on which it is to be used.