The 3D Preview Settings form contain settings that control how the Grid Editor Tool preview is shown in 3D.
Visible when editing 2D Grids
Center Marker
Cylinder Height: Height of the center cylinder half above and half below the surface
Cylinder Radius: Radius of the center cylinder.
Sphere Radius: Radius of the sphere
Preview
Dot Size: Size of preview dots
Dot Color: Color of preview dots
Visible when editing 3D Grids
Preview Material
Opacity: Opacity of the preview geometry object
Color: Color of the preview geometry object
Advanced: Shows the advanced Material Editor.