Visualisations range from annotated small scratch sketches to detailed renderings that demonstrate how a concept may be constructed, its components, form, structure, functions, ergonomic features or proportions. They allow the designer to think through, depict and document the design within their mind. Initial visualisations are typically in response to the initial research conducted whereas developed visualisations are used to communicate the details of the design to a client or user.
In each of the visualisations the designer can use a variety of freehand or instrumental drawing systems to communicate the design intent or feature they are trying to think through.
Scratch sketches are small rough sketches that are used to respond to research or quickly explore a wide variety of ideas within a short period of time. These drawings extremely simple and are often only for the use of the designer.
Thumbnail sketches are used to explore and develop ideas as well as identifying which ideas can develop in further detail. They are usually larger and contain more detail than scratch sketches. Thumbnail sketches can also be rendered with a variety of media to illustrate the elements and principles of design, materials, media, and surface qualities.
Concept sketches are larger and more refined than thumbnail sketches. Developed from rough sketches, concept sketches are typically rendered in coloured pencil and marker to provide a clear visual message and snap-shot about the concept's final direction. Since the linework and rendering style of these drawings can be consider informal, it can help promote to the clilent or potenial users that not all design decisions have been made. This can ensure that they consider themselves apart of the design process and able to offer suggestions to improve the final design.