A reference design is a design schematic, usually of a technical or construction project. In such a piece, information on measurements and systems requirements are often specified, but unlike some other types of design documents, it is presumed that the person using a reference design may make modifications and adjustments to suit his own purposes. Such documents commonly are developed by engineers, architects or other types of designers.
Depending on the complexity of the project, a reference design might be a single drawing or might be comprised of several drawings, each showing a different angle or component of the piece. Such drawings can accompany virtually any item that needs to be built, including houses or other structures, mechanical assemblies or technical systems. They are often included in consumer construction and craft books and magazines as well. A common example would be a woodworking book that provides plans for building benches, tables and other furniture.
Many people use the terms "reference design" and "blueprint" interchangeably. In fact, a blueprint is a very specific type of reference design, so called because the plotters on which these oversized schematics were printed used blue ink. Blueprints were also used almost exclusively by the construction industry, whereas reference designs might be used by any of several industries. Traditional blueprints are rarely used in modern times, having been replaced largely by computer printouts.
While the term is usually applied to detailed technical drawings, any type of assembly drawing might be called a reference design by some. This can include embroidery patterns and even the diagrams included in self-assembly pieces, such as furniture, toys and bicycles. In casual conversation and in some industries, the term is virtually interchangeable with "diagram" or "schematic."
Such designs include varying degrees of detail depending on the complexity of the project. Reference designs for homes, for example, include plans for both the actual building and, often, for subsystems, such as electrical, HVAC and plumbing systems. Most such designs also contain a key, which is a text section that tells the reader what different designations and abbreviations used within the diagram mean.
In some instances, the term "reference design" can also be used to describe something that has been built exactly according to the design. This means that it has not been customized in any way and that it in no way varies from the original design. When dealing with components, stock items used in a reference design are often more interchangeable than customized counterparts.