Geometric Theory

Polygons

Vertices

Edges

Geometric Theory

Geometric Theory

Polygons make up the surface/faces of the shape and turns a 3D skeleton into a shape.

Edges outline a shape and show each individual line that went into making a shape. Certain shapes have a larger amount of edges. For example, a curved shape will have a large amount of edges. This is due to the shape being made up of a large amount of straight lines.

If the surface of the shape was deleted, leaving only the edges outline, the shape would still be recognisable.

Vertices are sections where two edges meet. On the end of an edge's straight line there will be two vertices, one on either side.

As a large amount of edges are required to make a curve, more vertices are also required to create the curve. A box shape without a curve would require a very low amount of vertices.

Vertices are given coordinates to calculate their exact location. Each vertex has its own specific xyz coordinates.

Although the word polygons is used for 2D shapes, it is not used for 3D shapes.

3 sided shapes are known as trigons - a triangle.

4 sided shapes are known as quadgons - a square.

5, and more, sided shapes are known as n-gons - a pentagon.

Geometric theory revolves around creating and editing 3D objects.

There are many different elements that go into this process.

This includes:

Vertices

Edges

Polygons

Element

Standard primitives

Meshes

Polygon count

Element

Polygon Count

Standard Primitives

Meshes

Element is the combination of edges, vertices, and polygons to create the 3D model. Each 3D model is its own element. Combining more then one element into one expands on a simple 3D model.

Having each model as individuals makes it easier to single out and modify without changing the complete model.

Standard primitives are the basic shapes that make up a 3D model. They can be combined, edited, or morphed to become other shapes - but start off very basic.

Meshes are the combination of polygons to make a 3D model. Made up of trigons, quadgons and ngons to keep the model simple. As the model is made up of a large amount of polygons the outlines of each shape can be seen.

The mesh of a face could be made completely out of trigons or quadgons, adding more in curved areas, and less in smooth areas. Polygons can be removed from a mesh to give it a less detailed look, but make it easier to render.

Polygon count is important to 3D modelling as it outlines how detailed a model will be. If a large amount of polygons are used to make up the model it will be incredibly detailed.

However, there are reasons to not have a huge polygon count.

Rendering a 3D model with a large polygon count will take a larger amount of time to finish the rendering.

Whereas rendering a model with a lower polygon count would take a considerably less amount of time.

Another reason to reduce polygon count is that it can be impactful to games. If a large polygon count is used on everything it will take a longer time to process compared to a game that uses fewer. The difference in polygon count could make a game run at a higher, more desirable, frame rate - as well as make it more available to people with systems that aren't very powerful.

These standard primitives include:

Pyramid

Plane

Cube

Sphere

Cone

Cylinder