Understanding Basics of Texture Mapping
Texture maps as the very name suggest could be described as a two dimensional image file that is applied to the surface of 3D model to add color, texture and other surface details like glossiness, reflective or transparency. These square bitmap files are either created from a graphical software like Coral Draw or Photoshop or derived directly from a real – life photograph also Texture map files directly corresponds to the UV coordinates of an unwrapped 3D model. In a usual practice designers directly paint texture maps on top of the model’s UV layout which is later exported as a square bitmap file from any 3D software. Many a times designers work on layered files keeping UV coordinates on a semi-transparent layer which serves as the background guide for the designer to place specific details on Texture map layer. Let’s understand some of the important components of Texture Map.
Color Maps – as the name implies the primary and most pertinent feature of texture map is to add color and texture to the surface of a 3D Model this could be as simple as applying a golden texture on an ornament 3D Model or as complicated as color map application on an automobile (including metal body, mirrors, wheels, wind screen etc.)
Specular Map – Specular or Gloss map could be described as the set of instructions for the software defining portions on the image that should be shiny or glossy including the magnitude of glossiness. The nomenclature for these types of maps came from the fact that glossy surfaces like ceramics, metal, plastic or resin show a strong specular highlight i.e. the direct reflection from a strong light source. Specular map is grey scale image and absolutely essential for surfaces that aren’t uniformly glossy.
Bump, Displacement or Normal Map: A form of texture maps that assist in presenting more realistic indication of bumps or depressions on the surface of a 3D Model, Bump maps could be considered to be more complicated and complex as compared to the above two maps for example imagine a Brick wall mapped to a flat polygon plane and called finished, will that be looking realistic or convincing in a final render? Absolutely No because the flat play doesn’t react to the light the same way a brick wall with its cracks and coarseness would; in this case to increase impression of realism a bump or normal map would be added to more accurately recreate the coarse, grainy surface of brick.
Reflection Map – As the name implies, Reflection Map could be consider as the set of instructions for the software to understand which portions of the 3D model should be reflective; if in case the model’s entire surface is reflective or uniforms in nature Reflection map is omitted.
Transparency Map – Transparency map is quite similar to reflection map except it tells the software which portion of the model should be transparent.