Current location - Training Enrollment Network - Mathematics courses - What is 2D paper?
What is 2D paper?
D diagram is also called plan. The content of the second D diagram is only the horizontal X axis and the vertical Y axis. Traditional hand-made cartoons and illustrations belong to two-dimensional category, and their three-dimensional sense, light and shadow are all drawn by hand. Two-dimensional drawing software includes plane animation software photoshop, coreldraw, painter and flash, as well as professional two-dimensional drawing software such as autocad.

Corresponding to two-dimensional drawings are three-dimensional drawings: three-dimensional drawings, that is, three-dimensional space graphics, are used in modern processing and manufacturing, and three-dimensional animation also includes three-dimensional graphics. All three-dimensional graphics are in x-y-z three-dimensional space-time. Commonly used three-dimensional drawing software are: 3dmax, proe, ug, etc.

Extended data:

The following standards should be observed when making 2D plans:

1, Kuratovsky theorem

A taboo criterion put forward by Polish mathematician Kathemi Kuratowski (that is, graphs that meet certain conditions do not necessarily have certain properties) also includes the case of plane graphs. He put forward a theorem to explain:

A finite graph (a graph with finite vertices and edges) is a planar graph if and only if it does not contain a partitioned subgraph (a complete graph with five vertices) or a bipartite graph with three vertices. In graph homomorphism theory, a finite graph is a planar graph, provided that it does not contain any homomorphism or subgraph.

2. euler theorem

The plan divides the plane into several unconnected closed areas and the outer area of the figure. Among them, the outer region of the graph is called the outer surface of the graph, and each closed connected region in the graph is called the inner surface of the graph, which is divided by vertices and edges. Each surface contained in each surface graph corresponds to at least three edges.

There is a formula between the number of vertices, edges and faces of a planar graph, V-E+F=C+ 1, where v is the number of vertices, e is the number of edges, f is the number of faces, and c is the number of connected parts of the graph. When the graph is simply connected, the formula is simplified to V-E+F=2.

References:

Baidu Encyclopedia-Plan

References:

Baidu Encyclopedia-euler theorem

References:

Baidu Encyclopedia-Kuratovsky Theorem