The threshold has two functions: the first is to stop snakes and insects; The second geomantic omen is used to relieve qi in the opposite direction.
The height of the big threshold depends on the situation. General dimensions are 4 inches, 12 inches, 24 inches, 36 inches, or in terms of the size of the gate, it can be measured in centimeters or meters.
Strong directionality and high threshold; Small direction suffocation, small threshold height and other rules.