How do you transition between two materials?

I found this where RyanB explains (in the first answer) how to use the InterpolateMaterailInstanceParameters to transition between two materials. I’ve followed his directions to the letter, but it does nothing for me. The material never changes. Always just stays as the first material. Has anyone ever used this before or got it working? I’m stuck on how to transition between materials. I can’t just use textures within a single material. Has to be two separate material instances derived from the same parent material.

You need to use material instance dynamic instead of material instance constant (which are created through content browser), so you could create dynamic instances from the constant instances in your BP, assign the dynamic ones, then use InterpolateMaterialInstanceParameters.