Material Parameters and Instances in UE4

Software:
Unreal Engine 4.18

Material Parameters and Material instances allow you to create a customizable material template that can be easily reused with variations across the project.
In the Parent Material, you define the parameters that will be exposed for tweaking in the Material Instances.
Changing the Parent Material will affect all its instances.

Defining customizable parameters in the Parent Material:

1. Create 3Vector Constant. (press 3 and left click the blueprint background)
   * Parameters can also be created with other types of data like a Constant or a Texture Sample and more.
2. Right click the 3Vector node you created and choose Convert to Parameter.
3. In the Details Panel, name the parameter.

Creating the Material Instance:

1. Right click the Parent Material and choose Create Material Instance.
2. Name the Material Instance.
3. Double click the Material Instance to edit it.
4. In the Details panel, under Parameter Groups you will be able to edit the exposed parameters and create a variation of the material.

Related:
Material Functions
Blending Materials