A scale model is a physical model

Model (physical)

A physical model is a smaller or larger physical copy of an object...

, a representation or copy of an object that is larger or smaller than the actual size of the object, which seeks to maintain the relative proportions (the scale factor

Scale factor

A scale factor is a number which scales, or multiplies, some quantity. In the equation y=Cx, C is the scale factor for x. C is also the coefficient of x, and may be called the constant of proportionality of y to x...

) of the physical size of the original object. Very often the scale model is used as a guide to making the object in full size. Scale models are built or collected for many reasons.

Professional modelmakers often create models for many professions:

• Engineers who require scale models to test the likely performance of a particular design at an early stage of development without incurring the full expense of a full-sized prototype.
• Architects who require architectural models to evaluate and sell the look of a new construction before it is built.
• Filmmakers who require scale models of objects or sets that cannot be built in full size.
• Salesmen who require scale models to promote new products such as heavy equipment and automobiles and other vehicles.

Hobbyists or amateur modelmakers make die-cast models, injection molded, model railroads, remote control vehicles, wargaming and fantasy collectibles, model ships and ships in bottles for their own enjoyment.

Scale models can also be objects of art, either being created by artists or being rediscovered and transformed into art by artists.
Some modelers build and collect models made from a certain medium ( Metal, wood, plastic, card, paper, etc.).