The following example is meant for individuals who are not artists, but would benefit from a walkthrough of the progressive application of maps and property settings used by artists to create realistic materials.
Here is a basic model with no materials applied, it has 0 roughness and a slight metallic, to show the shadowing of the scene environment. Think of this as the “basic model”
These are the UVs of the model. The polygons of the 3D model, laid out on a flat plane. UVs are used to create maps and choose where certain things will be applied to the surface of the model.
This is a diffuse map, or “base” map. It is used to add the basic colours, details etc of the desired material. It has no properties of glossiness, depth, reflectivity etc., it’s almost like a basic sticker being added, and wrapped around the model. Think of wrapping paper, but only putting the design on.
With the Diffuse Map applied, it covers the model accordingly. It only adds this base layer of colours and no material properties. *Note certain things can be painted(colour changed) in to give it an appearance of highlights, shadows etc.,
Next, the Roughness Map. The way that this map works, is a 0-100 (White to Black). Where white is as rough as possible, and black acts as the most shiny spot.
With the roughness map applied, the model gets a much more dynamic range of roughness and shinyness. These maps are extremely helpful in adding detail to your model. (Think about putting a finger print on your smartphone, then note the changes in roughness where the finger-oil remains versus the regular screen in terms of how it reflects light back to you).
Usually the Metallic factor, 0-100 on the scale, ias used to adjust how Metallic the object appears. In this case, 0 White is the most metallic, and 100 Black is the least metallic. For example, 0 = Plastic and 100 = Chrome.
At times there are parts which are more metallic then otherss, so a Map is needed.
Next is the Normal map. These maps containRGB values which coordinate with the XYZ coordinates in 3D. This map is extremely helpful as it adds depth to your material, without having to add any extra polygons to the actual 3D model.
This is the appearance of the normal map now. Much more “texture” was added.
Here we have an Anisotropy map. This depends on the material as most don’t have an anisotropic factor, this is commonly seen in Herringbone fabrics.
The normal map has been removed so the effect of this map is more visible. Where the lines go through, the the Angle of Reflection is changed. This is seen in a lot of different materials, it is sometimes very mild and sometimes quite noticeable, as in the example above.
This is a crude example of all the above maps, and models. Overall, this is basically what artists have to do to make a material good/realistic. There is always a bit of further tweaking necessary until all maps line up perfectly to create the material that we want.