Konfiguracyjny charakter metody Monge'a

In the academic textbooks on descriptive geometry we meet with two various approaches to the Monge's method. There are the traced and untraced methods. Textbook authors usuallv prefer one of them ignoring sometimes the other method. In this paper we show that this problem have an essential geometrical sense. Namely, these methods are related to two differentg eometricalc onfigurations. Construction of the cofirmon point of two lines, belonging to the plane defined by means of traces (similarly as the construction of the refraction point of shadow of segment), leads to - so called - the Monge configuration (121,t3]) Whereas a construction of the comrnon point of two lines, lying on the plane determined by two intersecting lines, takes the configuration dual with reference to Veblen–Young configuration (based on the quadrangle's sextuplet of the points ([1], t4l)) The two configurations close themselveisf theorem of Desargues hold on the plane.