How to convert G channel into RGB?

Hi, it’s the first time I post here and I’m not sure if this is the right place for this topic, sorry if it’s not.

I’m learning UE4 by myself so this may be a basic question.

I have packed occlusion, roughness and metalic maps of a texture in an RGB image, and I want to use the G Channel in a layer blend node to paint the Terrain. It does not give me an error neither render the texture.

I think the problem is that G Channel is a float and layer blend expect RGB( which I don’t know what type of data it is).

So the questions:

  • Which node or nodes do I need between G Channel and Layer Blend?
  • And which type of data is an RGB image?