Geometric Theory uses shapes like polygons to create 3D models and objects depending on how you use the geometry. The more of these shapes you use within a 3D model makes the shape appear smoother that if you made it with less. Within the 3D software it allows you to place a material onto any of the faces of these shapes. This allows you to have complex shapes and have a interesting colour scheme.
There are three main contributions to the exterior of the model, Vertex, Edge and Face's. The Vertex is made up of points within a three dimensional space. When two of these vertices connect it becomes an edge. When three vertices connect it becomes a triangle, the simplest polygon. You can create more complex polygons by connecting multiple of these triangles together or by making a shape with more than three vertices connecting.
