How would i make an invisibility refraction material?

I am relatively new to making complex materials in UE4, and i thought it would be a good exercise to make a cloaked invisible character.

The effect i’m after is for light to refract around the mannequin, so you can see distortion where the character is, but it doesn’t work :S
UE$ HELP.jpg

I know i’m missing something very simple, and i haven’t grasped a lot of the concepts around materials. What changes should i make to get the result i want? :slight_smile: