I hope you have an idea and can help me please - I need to show the housing (A+B) and to blend out the upper half part B so that the inner parts can be seen later. I tried an animated alpha value and the upper part B disappears. But at the visible part A the part B is still visible, maybe reflections or shadows or both. So, I did a test and make B as glass with IOR 1 and it’s still visible. Why blocks the glass material the environment? Do you have an idea to avoid it?