When you think of trim, you might think of really elaborate molded pieces. But, in contemporary spaces you are executing an expression of rectilinearity and things like that.
Casing, as the trim around doors is called, has a strong impact on the overall style, appearance, and proportion of an opening as well as the overall style of your home’s interior. On the practical side, it conceals the gap between the door frame and the rough opening and helps to hold the frame in the opening.
Casing can be relatively plain, such as the popular clamshell design or square-edge design , or detailed, such as colonial-style molding.