eyeOffset
Gets or sets the Cartesian3 Property specifying the billboard's offset in eye coordinates. Eye coordinates is a left-handed coordinate system, where x points towards the viewer's right, y points up, and z points into the screen.
An eye offset is commonly used to arrange multiple billboards or objects at the same position, e.g., to arrange a billboard above its corresponding 3D model.
Below, the billboard is positioned at the center of the Earth but an eye offset makes it always appear on top of the Earth regardless of the viewer's or Earth's orientation.