UE4 Modification : Stackable Post Processing Materials

This is an Unreal Engine 4 modification to enable Stackable Post Processing Materials. Specifically, by default when Unreal sees 2+ Post Processing Material Instances of the same base Material, it will not apply both instances but a single one where all material parameters are blended together. This is not the behaviour some people desire.

You will need the source code version of Unreal and then build it from source because you need to modify the engine code in order to benefit from this custom behavior. There are numerous resources on how to do this online and this product does not offer that.

It is recommended that you are a programmer as the product is a unified git diff containing the source lines that need to be removed/added. Anyone can do them though as they are just a few copy-pastes of text away. This diff contains 6 lines additions and 1 line deletion.

The code also adds the option to enable/disable this behavior on a per base material basis so you can control where it's applied. The product image above shows an example effect/distortion being applied twice on a post processing volume and the difference between standard Unreal behavior and this modification which stacks the effects.