Edging can be defined as the control of the angle of the ski against the snow. All downhill ski´s have metal edges. Without edges skis would be hard to control. Attempting to change direction would be comical. Have you ever stood on two trays and tried to slide down a hill? If not, next time it snows, stick a crash helmet on, wrap yourself in bubble wrap and given it go. Make sure you have a friend handy to vídeo the outcome…the carnage that would ensue is sure to go viral on YouTube. After your little tray experimentation I am sure you will develop a new found affection for the little metal edges on your ski.
The edges combined with the sidecut are a key part of ski construction.
Inclination and angulation.