Volumetric Haptic Display Volumetric Haptic Display A Volumetric Haptic Display (VHD) is similar to a (visual) Volumetric Display, but informs touch instead of vision. A VHD projects a touch-based representation of a surface onto a 3D volumetric space. Users can feel the projected surface(s), usually with their hands. The display is otherwise not detectable, and offers no visual feedback. There are no known instances of a fully operational VHD at this time. The University of Bristol has developed a method for haptic feedback that could be integrated into a volumetric display. The system uses focused ultrasound to create a haptic objet in mid
Analogy of the sun region in which truth and real being brightly shine, it understands and knows it and appears to have reason; but when it has nothing to rest on but that which is mingled with darkness—that which becomes and perishes, it opines, it grows dim-sighted, changing opinions up and down, and is like something without reason. ('The Republic, VI: 508d; trans. W. H. D. Rouse) The allusion to "...that which becomes and perishes..." relates to all of that which is perceived by the bodily senses. The bodily senses make it clear that all visible things are subject to change, which Socrates categorizes