Many steps are needed from conceptualization to the very final product.
One of the most critical is the translation of the main idea or sketch into mathematical surfaces in 3D. The main concept should be kept and should fit in the technical package.
The earliest the 3D tools are used in the design development, the most efficient becomes the process.
3D data is used for validating a concept even before having any prototype. Rendering this data becomes in a powerful tool for evaluation, presentation and design decision making.