Because of its many advantages, 3D solid modeling has been replacing 2D modeling over the past few years. The realistic depiction of objects is a big advantage for manufacturers, allowing them to see how a product functions without actually spending time and money actually creating it. Another advantage of solid modeling is that product design can be changed frequently to ensure that it’s flawless, thereby improving efficiency.
In a solid model several features are incorporated unless and until the model becomes complete. All the solid models a handful of attributes are added unless and until the entire model becomes complete. One kind of modeling technique is ‘surfacing’ (freeform surface modeling) where all the surfaces are being defined, trimmed as well as merged, and also are being filled up in order to make it solid. Surfacing is more difficult, but better applicable to some manufacturing techniques, like injection molding.