Part of the appeal of sofa slip covers, is they can highlight the good features of a sofa or hide it's defects. Like someone with a perfect body, a well-designed sofa will look good with a variety of covers. But even the best furniture isn't suited for every room. So sofa slip covers can also be used to help the form of the sofa match the rest of the room.

Form and Function
The form of furniture should be related to its intended use. Straight back unupholstered chairs are suitable for dining room use, but not for relaxing in a den. And since usually a sofa is in a less formal room than a dining room, sofa slip covers should reflect that.

Form and Balance
The form of a piece of furniture should match the form of a room and be in balance with the other furniture. The balance can be either a formal or informal balance. A formal balance is symmetrical such as having identical tables on each end of a sofa. An informal balance achieves equality through use of various design elements such as color, line and pattern. For instance to shrink the apparent size of a sofa next to a chair, you could sofa slip cover of a cool color or a color that matches the walls or floor.

Form and Scale
There are two types of scale involved in a room's furnishings. The size of the furniture must be in proportion to the size of the room. And the size of the fabric patterns should also fit the size of the furniture. The same large floral design that would work for sofa slip covers would be totally out of scale for a dining room chair.

Form and Rhythm
Any repeated pattern contributes to the "rhythm" of a room. And the easiest way to repeat patterns is with form and color. A formal room tends to have tall straight forms while shorter rounded shapes fit a more casual setting. As with other design considerations, too much of the same repetition without a contrast is boring.

Form and Continuity
A house isn't just a collection of rooms. It's a group of rooms that have different uses but share common design elements. And although the forms of one room may not match those of another, they can have other things in common. For example, if the furniture style of a sofa doesn't match that of the other furniture, patterned sofa slip covers can be used to match the other room fabrics.