The definition of a material, normally, will be conducted using two or more shaders on the same object. The main difficulty is to determine the properties needed to create the desired effect that simulates the behavior of the material to light.
We shall see several examples that illustrate the materials used, including bump maps to give a realistic look to the surfaces.
In the material properties window select this option “Surface”:
The properties tab change to reflect the new possibilities of selection of the two “Shaders”. The variable “Fac” allows weight control or influence each “Shader” gives the final result. A null value indicates that the first “Shader” no effect. An intermediate value, 0.5, indicates a balanced mixture of the two, while the maximum permissible value, 1, indicates that only use the second.
Entering the node editor, see that the two are connected by a new type of node that corresponds to the mixer.
Applying the new material to an object can see the influence of the variable “Fac” in the final result:
If the value is “0”, using the first “Shader”, in this case “Difusse”
If the factor used is “1” the second will be used, in this case “Glossy”
Intermediate values held by both a mixture, eg: