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E. I. Gal'perin et al. 



surface with the interface as the geometric locus of the projection of 

 traces of intersection with the interface of the individual rays. 



Let us take a particular example in order to examine the technique for deter- 

 mining the projection of the points of intersection of the ray with the interface. 

 To do this we shall select from the total number of rays forming the conic 

 surface one ray for example with an azimuth of 70°. Its projection on the 

 horizontal plane is shown in Fig. 5, a, and the section of the vertical plane 

 along the lines /— /, that is in the direction of the ray in Fig. 5, b. Since 



(0) 



Fig. 5. Projection of point where ray intersects interface, a — plan; h — vertical cross 



section along direction of incidence of ray; 1 — structure contours of interface; I — I 



direction of incidence of ray. 



