Computer simulation has three meanings. Computer simulation can refer to a computer program that simulates an abstract model so that it can be studied and analyzed. It can also refer to a 3D computer graphics model made to represent a three-dimensional object through the use of specialized software. Finally, computer simulation can refer to the practice called emulation in which the functions of a particular system are reproduced on a second system.
A computer model, also known as a computational model, is a computer simulation widely used in the sciences and social sciences as an extension of mathematical modeling. A computer simulation of this type creates a sampling of representative outcomes or sequences of events in situations in which playing out all possible consequences of the model is prohibitive, and the models may be more or less abstract. Computer models are used in biology, chemistry, and physics, as well as economics and psychology. The typology of computer models categorizes them based on a set of four variables. Are they stochastic or deterministic? steady-state or dynamic? continuous or discrete? local or distributed?
Computer simulations in the form of 3D models are used in health care, the sciences, architecture, and most popularly, in motion pictures, computer games, and video games. Most 3D models take one of two approaches. On the one hand, they may show an object as a solid, defining it by its volume. The alternative is to show the boundary or shell of an object. This is the predominant model for games and film.
3D models may be formed in different ways. Like some learn-to-draw books, they can be based entirely on very basic geometric shapes. While the drawing books use circles, squares, triangles, and other 2D models, the computer modeling would use balls, cubes, and pyramids, for example. This style of modeling is called primitives because it is restricted to using primitive or fundamental shapes.
There are three other types of model formation. One is NURBS (Nonuniform rational B-spline), which was originated by two engineers who worked for French automobile manufacturers, Pierre Bézier and Paul de Casteljau. Bézier’s choice to publish his work resulted in his name being closely associated with the curves. NURBS are used in computer-aided design (CAD) programs, as well as programs for manufacturing, engineering, and animation.
Splines and patches modeling is similar to NURBS, with the surface being defined by curved lines. Polygonal modeling forms a polygonal mesh by using line segments to connect vertices. They are used in many 3D models, but can only approximate curved surfaces, because each polygon is planar.
The type of computer simulation known as emulation can allow one device to imitate another. This is useful, for example, in the case in which a particular computer peripheral brand has market dominance, and peripherals from other brands can emulate the dominant device for ease of use. Software emulators to run Apple software on other platforms and Windows software on Apple Macintosh computers is another use for this type of modeling.