3. Move it up a little bit
Any renderer will always have problems with overlap-
ping faces. Especially with transparent materials this
can cause visible problems. The glass bottom faces lie
exactly on the faces of the ground plane, they are in
the exact same location. Although it will not be very
visible here, it’s a good rule to remember, avoid coinci-
dent faces! Moving the glass up by 0.2 mm is already
more than enough.