Proximity hints during transform

[Pullusb]

Add directional openGL cone(s) or lines at object's border to use as hint for an easier placing

Other idea (probably too heavy): Raycast bottom and show distance as text

There could be a projection of the object on X/Z axis onto the surrounding surface (with color intensity for proximity ?)
This would be interesting as well when using translate gizmo to better ground a GP for example.
(As second visual cue to mark object bottom ?)