Abstract :
THE designer usually starts a new design by asking himself this question: “What features are absolutely required in this product for it to fulfill its function?” After this question is answered, he makes a preliminary design and often builds a model to see if the basic requirements are met. After they have been met, he asks himself a second question: “What additional features can be incorporated in this product to make it outstanding?” The final design usually, therefore, contains some features from the first category, which can be called “design requirements” and some features from the second category, which can be called “design improvements.”