Descriptive geometry

Summary

Descriptive geometry represents three-dimensional objects by two-dimensional drawings, usually several orthogonal projections, and solves spatial problems by constructions on these drawings. Its classical form is due to Gaspard Monge. There a point of space is given by its projections onto a horizontal and a vertical plane, drawn together on one sheet. From such drawings one can construct true lengths, true angles, intersections of surfaces and shadows. It was the theoretical basis of technical drawing in engineering and architecture.