When producing a prototype, a designer will need to constantly refer back to the design brief and design specification to ensure that the prototype fulfils the criteria that it set out to achieve. If, during this process, it does not meet one of the specification statements, then the designer will need to make changes - this is part of the iterative design process. If the final prototype does not meet the specification, then it is unlikely to be successful in the market place.
The prototype will need to demonstrate a wide range of making skills that have been conducted ny the designer with precision and accuracy. Precision and accuracy are about being exact. In terms of making, this involves ensuring that parts are measured out correctly and fit together exactly.
Precision can also refer to how materials are cut - manufacturers will lose money if too much scrap raw material is produced during cutting. Profits could be increased if they are able to find ways to lower the cost per product by saving material. Some manufacturers will pass on the savings that they make to the consumer and lower the cost of the product.
Tessellating shapes can help arrange items to be cut so that, when fitted together, as many as possible can be cut out of a sheet of material.
Nesting software will automatically fit irregular shapes as close together as possible. A designer could use a computer aided design (CAD) package with built-in nesting tools to try different nested shapes and work out what outputs use the least surface area of material.
Lay plans are used when cutting fabrics, as fabric has a nap. This means that it has a different appearance when viewed in another direction, and that pattern pieces cannot be tessellated or nested as effectively as wood, metal or plastic.