When you add a Gravity node, gravity forces are applied to all selected features in the physics interface with a density, mass, or mass distribution. You select boundaries, and all edges and points which belong to the selection are automatically included.
The gravity acts in a fixed spatial direction. The load intensity is g = ρgeg where
g as a default is the acceleration of gravity (a predefined physical constant). The action of gravity can also be seen as a linearly accelerated frame of reference.
