Class A surfaces

Class A surfaces is a term used in automotive design to describe a set of freeform surfaces of high efficiency and quality. Although, strictly, it is nothing more than saying the surfaces have curvature and tangency alignment - to ideal aesthetical reflection quality, many people interpret class A surfaces to have G2 (or even G3) curvature continuity to one another (see freeform surface modelling).

Class A surfacing is done using computer-aided industrial design applications. Class A surface modellers are also called "digital sculptors" in the industry. Industrial Designers develop their design styling through the A surface, the physical surface the end user can feel, touch, see etc.

The Class A surfacing is also termed as "Digital Sculpting" with numerous software tools now available in the automotive industry. The notable software tools are Alias by Autodesk, Icemsurf, Catia by Dassault systems etc.

A common method of working is to start with a prototype model and produce smooth mathematical Class A surfaces to describe the product's outer body. From this the production of tools and inspection of finished parts can be carried out. Class A surfacing complements the prototype modelling stage by reducing time and increasing control over design iterations.

Class A surfaces can be defined as any surface, that has styling intent, that is either seen, touched or both.

In an automotive application that means everything in the interior cabin and all of the exterior excluding the under body. This can also include beauty covers in the engine compartment as well as trunk panels and carpeting.

In the product design realm, Class A surfacing can be applied to such things like a housing for a hand drill, a plastic laundry detergent bottle, toys or furniture.

Aerospace has some styling considerations like bezels for air vents and lights.

Clay Modelling

Class A surfacing / digital sculpting is similar to clay modelling with the added advantage of computing power to change or incorporate design changes in existing/new design. More over the revisions of clay modelling and refinement iteration are carried out in digital version. The scanned data of a selected clay model will be taken as a "Point cloud data" input and Class A designers work on this Point cloud data to generate preliminary surfaces and further refine them to Class A surfaces.