A mesh is a collection of vertices and polygons that define the shape of an object in 3D computer graphics. Wiktionary has a definition of: Polygon For other use please see Polygon (disambiguation) A polygon (literally many angle, see Wiktionary for the etymology) is a closed planar path composed of a finite number of sequential line segments. ... The rewrite of this article is being devised at Talk:3D computer graphics/Temp. ...
Meshes usually contain only triangles for easy calculations, but can also represent objects made of general polygons with optional holes. A triangle is one of the basic shapes of geometry: a two-dimensional figure with three vertices and three sides which are straight line segments. ... Wiktionary has a definition of: Polygon For other use please see Polygon (disambiguation) A polygon (literally many angle, see Wiktionary for the etymology) is a closed planar path composed of a finite number of sequential line segments. ...
Examples of internal mesh structure representations:
simple list of vertices with a list of indices describing which vertices are linked to form polygons; additional information can describe a list of holes
list of vertices + list of edges (pairs of indices) + list of polygons that link edges
winged-edge data structure
The choice of the data structure is governed by the application: it's easier to deal with triangles than general polygons, especially in computational geometry. For optimized algorithms it is necessary to have a fast access to topological informations such as edges or neighbouring faces, this requires more complex structures such as the winged-edge representation. In computer science, computational geometry is the study of algorithms to solve problems stated in terms of geometry. ...
Polygons are used in computer graphics to compose images that are three-dimensional in appearance.
Usually (but not always) triangular, polygons arise when an object's surface is modeled, vertices are selected, and the object is rendered in a wire frame model.
This is quicker to display than a shaded model; thus the polygons are a stage in computer animation.
Polygonmesh models are distinguished by the fact that the geometric information is only available at the vertices of a polygon.
Polygon boundaries should be invisible in the final shaded version and some impression of the original surface that the polygonmesh approximates restored.
These are: on a polygon-by-polygon basis, where each polygon is rendered in turn, in isolation from all the rest; and in scan-line order, where the segments of all polygons in that scene which cross a given scan line are rendered, before moving on to the next scan line.
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