Figure 33 is an illustration of two meshing spur gears set against a blueprint style background depicting an engineering drawing of a spur gear. The meshing spur gears are 3D computer models. One gear is shown as a wire mesh model. Wire mesh is the term given to the outlines of the surface shapes used to create a solid model. Displaying only the outlines means that the viewer can see right through the gear seeing the edges of all the gears but may have difficulty discerning its true physical form. To overcome this difficulty the wire mesh model can then be rendered. Rendering is the process by which the various surfaces of the gear are coloured and shaded to replicate the physical appearance of the gear. The other gear has been rendered.