The boundary point of rain curtain on the ceiling, the specific distance should be judged according to the structure of curtain.

If a curtain is provided, the height of the Roman pole should be greater than the opening line.

If there is a ceiling or the size left is not large, the curtain can be smaller or close to the ceiling.

If the curtain uses a ring, the curtain rod will be much higher than the window, which can prevent the gap under the ring from seeing the window or the envelope.

If it is installed in a curtain box or equipped with curtains, it should be ensured that it can be adjusted at will without exposing the ring.