The texture map is a two-dimensional image file that can be applied to the surface of a 3D model (for example to create a 3D configurator) to add color, texture, or other surface details such as gloss, reflectivity, or transparency. Texture maps are designed to directly address the UV coordinates of an unpackaged 3D model and are either created from real photos or painted by hand in a graphics program such as Photoshop or Corel Painter.
Texture maps are usually painted directly onto the UV layout of the model, which can be exported as a square bitmap image from any 3D software package. Texture artists usually work in layered files, with the UV coordinates lying on a semitransparent layer that the artist uses as a guide for placing certain details.
Color (or Diffuse) Maps.
As the name suggests, the use of a color map serves to add color or texture to the surface of a model. This can be as simple as applying a wood grain to a table surface or as complex as a color map for an entire game character (including armor and accessories).
Texture maps play an important role in computer graphics beyond color and texture. In a production setting, the color map of a character or environment is usually just one of three maps used for almost every single 3D model.
The other two main map types are specular, bump, displacement and normal maps.
A specular map (also called gloss maps) determines which parts of a model should be shiny and which degree of gloss should be implemented. They are named because shiny surfaces such as metals, ceramics and some plastics show a strong gloss.
If you are nor sure about highlights, look for the white reflection on the edge of your coffee cup. Another common example of mirror reflection is the tiny white shimmer in a person`s eyes directly above the pupil.
A specular map is typically a grayscale image and absolutely necessary for non-uniformly shiny surfaces. An armoured vehicle, for example, requires a specular map to make scratches, dents and imperfections in the armour stand out convincingly.
Bump, displacement or normal maps.
Bump maps are somewhat more complex than one of the two previous examples. Bump maps are a kind of texture map that can allow a more realistic representation of bumps or depressions on the surface of a model.
A wall as an example: the image of a wall could be mapped to a flat polygon plane and described as completed, but it doesn`t look very convincing in a final rendering. For a flat surface does not reactas well to light as a wall to light as a wall with cracks and its coarseness.
To reinforce the impression of realism, one would add a bump or normal map to recreate the coarse, grainy surface of bricks more closely and reinforce the illusion that the cracks between the bricks are actually receding in space.
Of course, it would be possible to achieve the same effect by modeling each individual brick by hand, but a normal mapped plane is much more computationally efficient. The importance of normal maps in the game industry is high, because games without normal maps would never look like they do in reality today.
Bump, Displacement and Normal map deserve a discussion and are indispensable for creating photorealistic renderings.
Other important map types.
In addition to the already introduced map types, there are some more that you will encounter quite often.
The Reflection Map tells the software which parts of the 3D model to reflect. If the entire surface of a model is reflective or the plane of reflection is uniform, the use of the Reflection Map is unnecessary. Reflection Maps are grayscale images, where black is 0% reflective and white is 100% reflective.
The Transparency Map, on the other hand, determines which parts of the model should be transparent. A common use for a Transparency Map is an area that would otherwise be very difficult or too expensive to calculate, such as a chain link fence. Instead of modeling links individually, transparency can be convincing as long as the model is not too close to the foregorund and uses significantly less polygons.
Now you have learned about the different map types for editing surfaces in 3D models. In the following blog posts we will deal with this topic a little more deeply.