How to dynamically change post-process materials in BP?

[umayabashi]

Hello.
I would like to dynamically change the brightness of the entire screen using a blueprint.
For that, I created a post-process material (PM) and then added a post-process component to ThirdParsonCharactor,I decided to add a PM to that.

As you can see, PM allows you to change the brightness by changing the value of the parameter “Lumen”.

After that, use Dynamic Material Instance in BP
I tried to change the Lumen value dynamically, but this failed.

I set up the node like above and read the Lumen value as a variable, but although the value is 1.0, it is not reflected in the material.
The PM instance value at this time is set to 0.5, meaning that it has not changed from that state.

How can I make PM dynamically work with BP?
If you know any method please let me know.

[ClockworkOcean]

It is possible to get to at PP parameters from a PP reference, but it’s very clumsy.

A much easier way, is to make the material parameter part of a material parameter collection. Then all you have to do, is add the PP and use a single node to control it

[umayabashi]

Thank you!
Adding a Scalar variable to the material parameter collection
Adjust the brightness of the screen by adjusting the brightness with the Multiply node.
You have successfully changed it dynamically!
Thank you so much, ClockworkOcean.

[ClockworkOcean]

This is a great way to add material parameters to the sequencer, but for future reference, the PP parameter most appropriate to tweak to get the scene brighter is

Exposure compensation

I assume it’s exposed to the sequencer.