TouchSensor

Definition :
TouchSensor { 
  exposedField SFBool  enabled TRUE
  eventOut     SFVec3f hitNormal_changed
  eventOut     SFVec3f hitPoint_changed
  eventOut     SFVec2f hitTexCoord_changed
  eventOut     SFBool  isActive
  eventOut     SFBool  isOver
  eventOut     SFTime  touchTime
}
Explanation :

A TouchSensor tracks the location and state of the pointing device and detects when the user points at geometry contained by the TouchSensor's parent group. This sensor can be enabled or disabled by sending it an enabled event with a value of TRUE or FALSE. If the TouchSensor is disabled, it does not track user input or send output events.

The TouchSensor generates events as the pointing device "passes over" any geometry nodes that are descendants of the TouchSensor's parent group. Typically, the pointing device is a 2D device such as a mouse. In this case, the pointing device is considered to be moving within a plane a fixed distance from the viewer and perpendicular to the line of sight; this establishes a set of 3D coordinates for the pointer. If a 3D pointer is in use, then the TouchSensor generates events only when the pointer is within the user's field of view. In either case, the pointing device is considered to "pass over" geometry when that geometry is intersected by a line extending from the viewer and passing through the pointer's 3D coordinates. If multiple surfaces intersect this line (hereafter called the bearing), only the nearest will be eligible to generate events.

enabled :
hitNormal_changed :
hitPoint_changed :
hitTextCoord_changed :
isActive :
isOver :
touchTime :