NOVELTY - The device (200) has a support (230) and a transmission component (270) mechanically fixed to respective points (210, 220). The transmission component is mechanically coupled to the support such that the transmission component exerts a force onto the support when one of the points (220) moves in relation to the other point (210), perpendicular to an extension direction (130) of a component (160). A deformation sensitive sensor (390) is mechanically coupled to the support. The support reacts to the exerted force by deformation. The sensor detects deformation of the support.    USE - Device for detecting a distance value of a point from another point lying on an inner or outer surface of a component such as a hollow body i.e. rotor blade, of a wind power plant (all claimed). Can also be used for a solid material component, a tower of a wind power plant, a rotor wing of a tidal power plant, and a body of an aircraft, a ship and a submarine boat.    ADVANTAGE - The device efficiently detects the distance values of the point from another point along linear independent directions. The device allows an evaluation signal to be adapted relative to a signal impedance, a signal intensity, and value ranges, thus simplifying subsequent processing or use of the signal supplied by the device. The device corrects nonlinearities and defects, and reduces deformations and/or stresses during movement of the latter point to the former point in the transmission component. The device reduces stick-slip during pivoting of the component.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a rotor blade    (2) a method for detecting a distance value of a point from another point.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic cross-sectional view of a device for detecting a distance value of a point from another point.    Extension direction (130)    Component (160)    Device for detecting a distance value of a point from another point (200)    Points (210, 220)    Support (230)    Transmission component (270)    Deformation sensitive sensor (390)