For those already familiar with UE4's material system, hopefully this was a good review and came with some new information or pointers along the way. For those who were previously inexperienced, you should now have a solid foundation to build upon for driving a team and project forward and making the right decisions with the most commonly used powerful tools that Unreal makes available. There is always more to learn, but having a level of competence across areas such as this is mandatory for being able to take a project to a higher level and demonstrate to a team the skills and knowledge needed to manage such a complex and powerful world that UE4's materials offer every project. Finally, as promised, for those familiar with writing HLSL or GLSL directly, and wondering what this looks like for UE4, take a look in the Engine's Shaders/Private folder at things such as VolumetricFog.usf. For those who want to get started down this path or who are new to Unreal's way of compiling shaders themselves, another great link is in the Further reading section for just that pursuit.