PBR : Refraction not showing for MeshStandardMaterial. Is it supported?

Questions
1

Here’s my PBR texture-from-canvas demo - sadly missing refraction.

Is it supported? If so - could someone have a quick peak at what I’m missing?

2

There are a few examples demonstrating refraction, have you looked at those?

3

Hi!

I have seen those - they don’t use the PBR standard material. =(