4.24 - Material Function Instance prefix not working

I’ve been trying to use Material Function Instances as a way of simplifying the process of adding layers to Landscape materials. There’s a few issues I’m having but I think I pinpointed the cause. I made a simple test with just two MFIs (Material Function Instances) and no matter what I chose in the landscape it only paints one of them. But I suspect my problem actually comes from Material Function Instances not working as intended.

Here’s setups:

This is my Landscape Material with the two MFIs attached

Material Function Instance 1

Material Function Instance 2

Here is a small snipped of the Material Function parent and how I’m using the parameters. Not using inputs, only parameters because I’m instancing the MF (like you would with materials and material instances)

This is what I suspect is actually causing the issue. The prefix appears to do nothing at all.

300067-unrealbug-005.jpg

If I create my landscape material using all this and make an instance of that. There’s only one of MFIs in the material instance editor showing up in the properties list. My guess is that since prefix is not doing anything, the shader is assuming the data of just one, because all the parameters and groups have the exact same name.

Anything I tested with MFs and using that flag, seems to change nothing. I can never see this “unique index” anywhere which why I think this is the root of all evil in my current problem. This is true even for making copies of material functions as opposed to instances of them.

Alright, thank you!

btw - i would like to also point out that when you put a material function expression call into a material you cannot browse for material function instances. The only way to be able to get them into your material is by dragging them into the material from the content browser. So it appears that the whole pipeline for material function instances is just… not complete?

another btw - it would seem that using Material Function Instance in materials in 4.25 straight up crashes Unreal.

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Thanks

Does this feature exist or works in Unreal 5.0.3? It is really needed.