Patent ID: 7171759

Claim:
A method to measure the orientation angle between two surfaces comprising: A. a first frame that is aligned to a first of said two surfaces, B. a second frame that is aligned to a second of said two surfaces, C. a continuous string that is routed in a defined path from said first frame to said second frame and ending at said first frame, D. where said defined path incorporates two segments between said first frame and said second frame, E. where said two segments define a plane, F. where said continuous string is placed under tension a first time and a position of said continuous string relative to said second frame is monitored, G. where said first frame and said second frame are realigned to said two surfaces in a way that causes said position of said continuous string to change in a predictable manner on said second frame when placed under tension a second time, H. where said predictable manner is related to said orientation angle between said two surfaces, whereby said orientation angle between said two surfaces is determined in said plane.