The iterative design process helps to develop designs, focusing on improving them and making them more successful. It is important at this stage for designers to consider the design as a whole, rather than the separate components in isolation. It is also crucial for designers to consider user feedback in their design decisions as it will help generate and evaluate new developmental ideas and produce a successful chosen design.
Developing ideas will highlight areas of uncertainty that may require further research to strengthen the success of the idea:
Modelling can be time-consuming and expensive, but a physical model allows a person to see and handle a product unlike viewing it on a screen through computer aided design (CAD). computer aided manufacture (CAM) models made on a 3D printer using a CAD drawing are very accurate but also expensive, time-consuming and limited to 3D-printable materials. Designers can use easy-to-form and easily accessible materials, eg balsa, jelutong and cardboard, to create cheap models quickly and cheaply.
Quick textile designs can be modelled out of newspaper and more detailed models can be made from cotton or calico. Fabric models are called toiles and can be made on a mannequin to test the dimensions and drape of a garment.
Breadboards are used in the early development of electronic products. They are boards containing a series of holes that electrical components can be pushed into to allow current flow without making a permanent join. Components can then be easily swapped to improve the function before making the final circuit.
Prototypes can be full-size, working models of a product, and are the next stage of development after modelling. They are often made from the same material as the product and often have fully functioning parts. Prototyping is expensive, so a product needs to have already been modelled and tested.
Prototyping can help work out the cost of manufacturing a product, including how much material is needed and what machinery is required. The percentage profit can be worked out from this and can be improved by lowering production costs, for example by using cheaper materials or fewer workers.
Once a prototype has been made it can be tested in a variety of ways:
Throughout the iterative design process, the design ideas and models or prototypes will need to be analysed and evaluated to inform the choice of design to take forward, to make modifications and to develop into the final chosen design solution. The designer will also need to consider:
These consideration, as well as the design brief, design specification and feedback from the user, must be constantly utilised to ensure that the designer stays on the right track and produces a successful chosen design.