Descriptive geometry is the branch of mathematics concerned with the representation of spatial figures in the plane. It allows us to draw spatial figures on paper. Thus, an architect draws building plans, a lathe operator uses engineering sketches to produce parts, a chemist shows the spatial arrangement of atoms of substances, a cartographer makes maps of cities and landscapes, and an astronomer portrays the starry sky.
Monge projection
This is a rectangular projection on two perpendicular projection planes. Not only does it allow spatial figures in the plane to be displayed, but their properties such as dimensions or position in space can also be derived from the drawings. In technical drawings, multiple display planes can be used if a solid shape requires representation.