What defines a surface model in design?

A surface model in design refers primarily to the way a product's exterior is represented. This modeling technique emphasizes the visual and aesthetic aspects of a design, allowing for a realistic representation of the product before it is fully realized. This means that when creating a surface model, designers focus on the geometric and visual qualities, making it an effective tool for visualizing the final appearance of a product, including surface finishes, materials, and contours.

In contrast, the other options highlight different aspects of modeling and design processes. The independent creation of parts reflects parametric modeling but does not capture the essence of a surface model. Detailed machining data pertains more to solid modeling, where functional and manufacturing details are crucial. Modeling the complete product from start to finish describes a comprehensive approach typical of design processes that utilize solid models rather than just surface representations. Therefore, the defining characteristic of a surface model is its focus on creating a realistic visual representation of the final product.