I've created a grid and moved it by 2000 mm in the Z direction. Now I can see the grid in the correct position in an elevation view, but it disappeared from the 3D view. I have extended the view depth of the 3D view but the grid is still invisible. Why doesn't it show?
A grid represents a three-dimensional complex of horizontal and vertical planes as illustrated in the image below:
The projection of the grid planes is scribed on the view plane using dash-and-dot lines. View depth has no effect on grid visibility - the grid is only shown on the view if any of the grids' planes touch the view plane. So if your view plane is at Z = 0 and your grid's lowest XY plane is at Z = +2000 and the extensions of the grid are less than 2000 mm, then none of the grid planes reach the view plane, and as a result the grid cannot be seen in the 3D view.