Polygon mesh
From Wikipedia, the free encyclopedia
A polygon mesh or unstructured grid is a collection of vertices and polygons that define the shape of an polyhedral object in 3D computer graphics.
Meshes usually consists of triangles, quadrilaterals or other simple convex polygons, since this simplifies rendering, but they can also contain objects made of general polygons with optional holes.
Examples of internal representations of an unstructured grid:
- 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 information such as edges or neighboring faces; this requires more complex structures such as the winged-edge representation.
