How to determine the orientation of houses in residential geomantic omen, such as the lack of northwest corner, which affects children, is it based on the north-south orientation of compass or other standards (facing north? )

First find the center of the house and measure it in the direction of the missing corner. But generally speaking, the indoor magnetic field is chaotic and cannot be measured accurately indoors. The correct way is to find a wall that can see your house from the outside (at least two meters away from the wall), measure the direction of this wall, go back to the house, and radiate in eight directions in the center of the house according to the direction measured from the outside, and you will know that the missing corner is in that direction.

Of course, the compass is the best measuring direction, but if you just want to know the direction of the missing angle, the general compass is enough.