The essentials of descriptive geometry . Fig. 104. ?equal in length; therefore, with o as a center and ol as a radius describe the arc i 16, etc., and at any convenient point draw the line ogi equal to ogi. This line will be thefirst element in the development. Now divide the circle of thebase into a convenient number of parts and step these off on CONICAL SURFACES 127 the developed base as i, 2, 3, 4, 5, 6, etc. Find where each of theelements pierces the plane through ag and jfind the true distancefrom 0 to each point. Lay this distance off on the development. \\ \ \ \ \ \\\ \ \ \ v\\ \ as at
The essentials of descriptive geometry . Fig. 104. ?equal in length; therefore, with o as a center and ol as a radius describe the arc i 16, etc., and at any convenient point draw the line ogi equal to ogi. This line will be thefirst element in the development. Now divide the circle of thebase into a convenient number of parts and step these off on CONICAL SURFACES 127 the developed base as i, 2, 3, 4, 5, 6, etc. Find where each of theelements pierces the plane through ag and jfind the true distancefrom 0 to each point. Lay this distance off on the development. \\ \ \ \ \ \\\ \ \ \ v\\ \ as at g, f, e, d, etc. In the figure only a few points have beenworked out to avoid the confusion of lines but in practice theelements should be spaced about as shown by the points i, 2,3, 4, etc. 128 ESSENTIALS OF DESCRIPTIVE GEOMETRY Since the development will be symmetrical about a center lineOi6 the two parts may be constructed simultaneously. Construction. Method of Triangulation. When the givencone is oblique. In Fig. 105 the given cone is taken with itsaxis parallel to V with its base in H and its apex at 0. Layoff o8 equal to element 08. Now with the true length of thearc 7-8 as a radius and 8 as a center strike an arc, and with oas a center and the true length of 0 7 as a radius strike a secondarc intersecting the first at 7. o7 then is the position in thedevelopment of the element O7. In practice the distance 8-7must be made small enough so that the triangle o87 will Heon the surface of the cone; in the figure these lines are takenfar apart to avoi
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Keywords: ., bookcentury1900, bookdecade1910, bookidcu3192400462, bookyear1915
