Model building is a hobby and career that involves the creation of physical models either from kits or from materials and components acquired by the builder. The kits contain several pieces that need to be assembled in order to make a final model. Most model-building categories have a range of common scales that make them manageable for the average person both to complete and display. A model is generally considered physical representations of an object and maintains accurate relationships between all of its aspects.

The model building kits can be classified according to skill levels that represent the degree of difficulty for the hobbyist. These include skill level 1 with snap-together pieces that do not require glue or paint; skill level 2, which requires glue and paint; and, skill level 3 kits that include smaller and more detailed parts. Advanced skill levels 4 and 5 kits ship with components that have extra-fine details. Particularly, level 5 requires expert-level skills.