Descriptive geometry for students in engineering science and architecture; a carefully graded course of instruction . ock are equally inclined to the \ A short edge of the upper is m the \ .P. The realinclinations of the rays are 50° to the ;. and 30° to the Find the shade and shadows 4 \ right circular cone, 2 high, 2 diameter of base, stands vertically on the centre of asquare block, i thick, sides 3- The block has one rectangular face parallel to the \ .1 ^andi from it. The rays of light have plans at 45° to XY and elevations at 30 to A Y. I-md the shade and shadows. r
Descriptive geometry for students in engineering science and architecture; a carefully graded course of instruction . ock are equally inclined to the \ A short edge of the upper is m the \ .P. The realinclinations of the rays are 50° to the ;. and 30° to the Find the shade and shadows 4 \ right circular cone, 2 high, 2 diameter of base, stands vertically on the centre of asquare block, i thick, sides 3- The block has one rectangular face parallel to the \ .1 ^andi from it. The rays of light have plans at 45° to XY and elevations at 30 to A Y. I-md the shade and shadows. r wu , 5. Prepare other exercises, using your best judgment, and work them out for further practice. PART TWO CHAPTER VII RABATTEMENT OF PLANES, AND PROJECTIONS OF FIGURESINVOLVING ITS USE Section 13, The process known as rabattement is that by which a plane ismade to swing on one of its traces, as on a hinge, until whatever is represented asbeing in the plane, whether it be point, line or figure, is turned into one of theplanes of projection, and its true form is made evident, also its relation to the trace of. Fig. 42. the plane. In Fig. 42 the plane RST, arranged perpendicularly to the , hasin it a point P. If the plane is made to swing about its trace 5r as a hinge lineuntil it is turned over into the , either on the one side or on the other, it carriesthe point with it, and the points rabattement is said to be at P2 or at P3. If D bea point perpendicularly opposite P, and in the or hinge line, then DP maybe considered as the radius line for an arc in which the point P moves. Thisradius length, as shown in the figure at (ii), is the hypotenuse of a right-angledtriangle having for its base the perpendicular distance from the plan p to the 40 RABATTEMENT OF PLANES 41 trace at d, and for its height the distance from Al to p. The right angle at c inthe figure should be specially noted. In Fig. 43 an oblique plane is represented at RST and a point P in it withplan
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisheretcetc, bookyear191
