OTHERS CASES THAN CONVEXES POLYHEDRONS




The ridges are equidistant from the corresponding edges of the plate.

The ridges correspond to segments or parts of conics.


RIDGE BETWEEN A RECTILINEAR EDGE AND A CIRCULAR ONE






In both cases : The ridge is a PARABOLA with focus O and directrix (D)


RIDGE BETWEEN TWO CIRCULAR EDGES


The ridge is the ELLIPSE with center of the circles being the focus.

OM + OM' = R + R'

The ridge betwen the of two holes is an HYPERBOLA.




CASE OF A CONCAVE POLYGON


 

The arrows indiacte the path of the sand .
A cone with top O.

 

 

 

(P) is the parabola with focus F and directrix (D).
(P') is the parabola with focus F and directrix (D').

 





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