In this tutorial series i am going to implement a special material to render planets. When we render planets, we can’t rely on the main directional light as we have to adjust it to get the desired look of the scene. So, I am going to implement an unlit planet material with the ability to show a fake shading effect with a parameter that defines the light direction to make the planet look like it is lit by light. So, it can have a lit side and a dark side similar to a default lit material.
https://dev.epicgames.com/community/learning/tutorials/vv7b/unreal-engine-planet-rendering-materials