UV Mapping is the process of unwrapping a polygonal mesh to create a 2D image to apply a texture to, then applying that image to the 3D model, giving it colour and texture. This stage usually occurs after the modeling process. U and V represent the axes of the 2D texture, as X, Y and Z are already used to denote 3D space in modelling software.
A 3D model and its 2D UV map.
The process of unwrapping the mesh can be done automatically or manually through the process of assigning seams along the edges of a mesh. This creates an image that resembles a clothes pattern, which can be painted, or have a picture or texture map applied onto it. When this image is applied back onto the 3D model, it creates the appearance of it having a texture.
The ball on the left displays what happens then an image is applied to a mesh without first unwrapping it. The ball on the right had been UV unwrapped before having the image applied.
Wikipedia,. (2015). UV mapping. Retrieved 21 February 2015, from http://en.wikipedia.org/wiki/UV_mapping
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