Gravity
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.
Shell Properties
As the a gravitational load always acts on the entire structure, it is not possible to select individual layers. The selection in this section only acts as a filter for the boundary selection.
All other settings for the Gravity node are described in the documentation for Gravity in the Solid Mechanics interface.
Location in User Interface
Context Menus
Ribbon
Physics tab with Layered Shell selected: