The essentials of descriptive geometry . Eye-^gj^L^-^. Fig. 1. lines. In other words, some Unes are foreshortened more thanothers owing to the position of the eye. It will also be observed that in perspective more than one faceof the object is seen from one point of view. 4 ESSENTIALS OF DESCRIPTIVE GEOMETRY 6. In engineering drawing —? or in orthographic projection —the eye of the draftsman is assumed to be at infinity. Therefore,the lines of sight do not converge but are parallel. If now, as r4 \ \ \ \ To the eye ^ Object \ \ \ \ Fig. 2. in Fig. 2, a plane be set up between the eye and the o
The essentials of descriptive geometry . Eye-^gj^L^-^. Fig. 1. lines. In other words, some Unes are foreshortened more thanothers owing to the position of the eye. It will also be observed that in perspective more than one faceof the object is seen from one point of view. 4 ESSENTIALS OF DESCRIPTIVE GEOMETRY 6. In engineering drawing —? or in orthographic projection —the eye of the draftsman is assumed to be at infinity. Therefore,the lines of sight do not converge but are parallel. If now, as r4 \ \ \ \ To the eye ^ Object \ \ \ \ Fig. 2. in Fig. 2, a plane be set up between the eye and the object andthe points where the Knes pierce this plane be found and joinedthe result will be a picture of the object not as it appears but asit actually is, and each line of the picture will be the same lengthas the corresponding hne in the object. ORTHOGRAPHIC PROJECTION 5 It will be observed, therefore, that the size of the picture doesnot vary with the position of the picture plane. No matter wherethe plane is placed the size of the resultingcu31924004629899
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Keywords: ., bookcentury1900, bookdecade1910, bookidcu3192400462, bookyear1915
