This tool enables easy drag-and-drop functionality for 3D physical objects.

1. Add the `DragDropController.gd` as an `AutoLoad` (aka singleton) to your project.
2. Populate your 3D scene with physical objects
3. As a sibling to the Physics object (e.g. Area, KinematicBody, RigidBody, etc...), add a `Draggable` node
4. Register to the signals of the Draggable node as you see fit, especially the `drag_move` signal

The DragDropController uses raycasting to detect where the mouse is hovering over (excuding the dragged object).
Use this signal to update the position of your object as it is being dragged. It is done this way since you may want a snapping, animation, or something else, so it is for you to decide.
The signal sends two variables, the draggable object and the raycast dictionary output (see https://docs.godotengine.org/en/3.2/classes/class_physicsdirectspacestate.html#class-physicsdirectspacestate-method-intersect-ray for more details)

As an example, you may want to receive the signal as the following to simple slide over the collider object:

func _on_Draggable_drag_move(node, cast):
set_translation(cast['position'])

Remember to use pivot points or references to properly position and avoid object overlaps.

There is an example project provided where a draggable box slides above a plane.