# Geometric model

A geometric model describes the shape of a physical or mathematical object by means of geometric concepts. Geometric model(l)ing is the construction or use of geometric models. Geometric models are used in computer graphics, computer-aided design and manufacturing, and many applied fields such as medical image processing.

Geometric models can be built for objects of any dimension in any geometric space. Both 2D and 3D geometric models are extensively used in computer graphics. 2D models are important in computer typography and drafting. 3D models are central to computer-aided design and manufacturing, and many applied technical fields such as geology and medical image processing.

Geometric models are usually distinguished from procedural and object-oriented models, which define the shape implicitly by an algorithm. They are also contrasted with digital images and volumetric models; and with implicit mathematical models such as the zero set of an arbitrary polynomial. However, the distinction is often blurred: for instance, geometric shapes can be represented by objects; a digital image can be interpreted as a collection of colored squares; and geometric shapes such as circles are defined by implicit mathematical equations. Also, the modeling of fractal objects often requires a combination of geometric and procedural techniques.

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