Polygon Modeling

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Polygon Modeling

http://en.wikipedia.org/wiki/Polygonal_modeling

Polygon modeling refers to a modeling method that interacts directly with vertices, edges and faces of a mesh. A polygon refers to a plane shape that is named based on the number of sides. Digital modeling typically refers to the polygon as a shape that is composed of two faces, typically four vertices and 5 edges.

Components

A vertex refers to an infinitely small point that defines a location in space.
Edges connect two vertices and are infinitely thin.
Faces or Triangles are the product of three vertices and three edges and the surface has a direction or normal to determine the render-able side.

Topology refers to the sharing of edges and vertices to create continuous mesh surfaces. http://en.wikipedia.org/wiki/Topology

Modeling Techniques

There are several techniques that apply to polygon modeling; primitive modeling, box modeling and extrusion modeling.

Primitive modeling refers to the creation and arrangement of geometric primitives; boxes, spheres, cylinders, etc, in order to create meshes to create the desired model. Typically geometry can be joined through Boolean operations such as union, subtraction, and intersection.

Boolean Union of Polygon Plane and Polygon Box

Box modeling is a form of modeling where the modeler creates a rough draft or approximation of the final desired model. A smoothing operation or subdivisions are then used to add the desired refinement. It is a quick modeling method, especially compared to editing each individual vertex but it can be difficult to get the desired results because of the uniformity of the smoothing operations.

Example of Box Modeling

Extrusion modeling refers to a method of modeling that starts from a two dimensional shape (polygon) that resembles an orthographic view of the desired subject. Geometry is then extruded from this shape to match a perpendicular orthographic view.