5. Reflect on backside
Notice the dark border on the inside glass surface? To get rid of this, we will turn on the ‘reflect on backside’ option in the options rollout of the glass material.
Render again to see the difference.
This option creates internal reflections, an effect that happens in real life too.
This is the base of our glass material. It is
100% clear, very reflective glass.
Assign to the glass object and render. It should look like my example.