Waiting the eventual release of FramewokElement3D and Control3D, I built in Perspective 0.4 a system based on UIElement3D and 3D basic objects of this library. This system, although simple and rustic, respects the principle of separation of the function and the visual appearance of controls. And it still implements a skin mechanism.
The provided controls are interactive buttons : Button3D, Fader3D and Knob3D. Incidentally, their equivalents in 2D (Fader, Knob) are also offered.