Unreal Engine 4 introduced a new depth buffer along with their PBR rendering system. It's called "Custom Depth" and can be used for effects like the selection outline that is built-in the Editor, rendering of occluded meshes or custom culling of transparency. I will discuss some of the basics of using this buffer in the material editor and explain some of the features I used it for in my own projects. When using Custom Depth it's important to read through the Issues & Limitations at the bottom of the page to prevent you hours of headache and...