Drag & Drop ModelVisual3D

Hi!. Congratulations for this great library. I am using Helix + Petzold ModelVisual3D drag and drop within a 3D scene. I wonder if it would be possible with Helix similiar effect to which the application is made in Rhinoceros. How they get that dragging a ModelVisual3D with the mouse remains static back home in his position?

You should create a copy of the visual while performing the manipulation. I think you can add the copy to your scene when the manipulators mouse down event is raised and remove it on mouse up.
I think this should be handled by the application, not by the Manipulator classes.