Texture mapping is the act of placing a two-dimensional image (2D) onto the surface of a three-dimensional (3D) object within a digital environment. There are various types of texture maps that can be applied to a 3D object and each achieves a specific result. These texture maps are designed to reflect the UV mapping coordinates of the 3D model that has been UV unwrapped.
Texture maps can be made from photographs or hand painted in a digital paint program such as adobe photoshop. These texture maps are usually applied/painted directly onto the UV Unwrap of the 3D model. UV Maps are generated within the 3D application from the 3D model and can be exported as a 2d bitmap image.
I will now list the various types of texture used within 3D software:
Diffuse maps are the maps that add colour or texture to the surface of a model. For example bricks, metal, rust, wood or skin. A character or environments diffuse map is usually just one of three maps that will be used for almost every single textured 3D model.
Specular maps set specific areas of the 3D model to be shiny. Specular maps work from Black through the entire range of Grey through to White. The level of white in a specific area defines the intensity of this shine. The whiter it is, the sharper the gloss. Good examples of this effect in real life can be seen on shiny surfaces, like metals, ceramics and plastics.
Normal maps are used to define a greater level of detail through bumps and indents within your textur, giving a more realistic look to the surface of your model. Picture the tactile surface of a brick wall. it has areas that indent where the cement in-between the bricks are and the bricks themselves have a stucco look and feel to them. You could just place a photograph of a brick wall on a flat place. However this will not react to the light source in the same way a realistic wall would. Adding a normal map enables the computer to calculate the high and low spots of your texture and apply shadows and highlights appropriately.
The 3D games you play today would not look as they do if it werent for the industry’s use of normal maps.
Diffuse, Specular and Normal Maps are the main textures used within games, they are applied to almost everything you see in a 3D environment. In addition to these three textures there are two other main textures that you should consider.
Reflection maps inform the software what areas of your texture/model should be reflective. Like specular maps, reflection maps are grey scale images, where black is not reflective and white is highly reflective.
These maps indicatewhat areas of the texture should be omitted, making these areas transparent. These are often used for items like nets, chain link fences, cables and trees. To use an alpha map for netting rather than modelling the net, greatly aids in the reduction of polygons.
And when you apply together, diffuse, specular, normal and reflection it gives you a much better texture alot more realistic look to it. It all depends on how you want your texture to look if you just want a normal brick wall a diffuse and normal map should do.