This means that the force needed to deform the entire Himalayan mountain chain is larger than the force needed to produce a cm scale fold within the Himalayas. What often remains constant across all scales is the stress needed to produce deformation. As the size of a material body gets larger, the force needed to deform that body gets larger. However, the area of the plane across which the force is applied also increases. This means that the stress applied across the plane remains constant.
Force has both direction and magnitude.
Like force, the stress across a given plane has both direction and magnitude. The direction of a stress is the same as that of the applied force. As with forces applies across planes, is often convenient to break the stress acting on a plane into 2 components.