Solid modeling lets us creates a virtual 3D representation of components for machine design and analysis. The ability to dynamically re-orient the model, in real-time shaded 3-D, is emphasized and helps the designer maintain a mental 3-D image. Design work on components can be on individual parts or in assembly modeling methods.
A solid model generally consists of a group of features, added one at a time, until the model is complete. Solid models are built mostly with sketcher-based features; 2-D sketches that are swept along a path to become 3-D. These then are extruded to creat a solid. After a solid has been created you can then cut, extend, shell and revolve just to name a few.
Another type of modeling technique is Surfacing Modeling. Here, surfaces are defined, trimmed and merged, and filled to make solid. The surfaces are usually defined with curves in space and a variety of complex commands. Surfacing is more difficult, but better applicable to some manufacturing techniques, like injection molding. Solid models for injection molded parts usually have both surfacing and sketcher based features. The sample here is just a idea on creating a solid model then shelling it ( input to wall thickness is required) and a few fillet edge commands applied. The finished model can have a wide veriaty of surface textures applied to it to give the model a realistic finished look.