Random colour in post process material. Error with wrong float.

[KingKerel]

I am attempting to have a blueprint able to randomly change the colour of a post processing material.
For now its just a simple overlay that makes everything a certain colour.
I simply multiply a “SceneTexture:PostProcessInput0” with a colour.
For this colour I used a Float3, which did not work.
Then I used a Float4, which did work.
When I changed the Float4 into a parameter, I got an error indicating I used the wrong float type.

From what I could find online, if you want a different colour in post processing, you have to define each of them individually with a lot of nodes and use a custom stencil for each.

Cant I just pass a random colour to the post process material somehow?

[RecourseDesign]

Hi KingKerel,

Try this: (a good tip for casting parameters to float3 or float4 in any situation)

[Doc.gdi]

First, you probably want to mask(componentMask) that scene texture to rgb only so it wont complain.

And to pass a random colour to the postprocess material I think that you can not use dinamic instances in postrpoces (don’t know why, maybe I’m wrong).

But what i’m sure you can do is to create an material collection parameter (in the same folder as the material for example) and in that MPC add a vector parameter and call it in the material.

Then in any bp (but most common in the player or level) create a mcp variable and asign the one u made. Then from that variable drag the set vector collection parameter node and select your vector. And as parameter just add a random vector

[KingKerel]

Thanks for the tips!

I spend an entire day just figuring out a viable way to get those parameters in a post process material working.
It seems everyone has difficulty working with parameters in post process materials.
Even seen posts from 2014, and it didnt get much easier today.

I only got it to work by making a new “Dynamic Material Instance” and overriding what is in the “Post Process Volume”.
However trying to access the editor assigned “Post Process Material” in a “Post Process Volume” is a lost cause.
I just could not get it to work.

The option with the “MakeFloat4” node worked for me. I can now push random colours to my Post Processing Material.

I also explored the option with the “Material Parameter Collection”. This also works.

The tip about the masks to convert float4 to float3 was also nice.

[KingKerel]

Apparently I cant tag two posts as the answer, but your tip about “Material Parameter Collection” also worked.