72 The father of perspective is the Italian architect Filippo Brunelleschi (1377-1446) who observed that, with a fixed point of view, parallel lines appear to converge at a single point in the distance. isOMeTRiC DiMeTRiC TRiMeTRiC axe: asse to recall: richiamare view: vista 174 MeCHAniCs TYPES OF REPRESENTATION The projection technique Drafters can reproduce a three-dimensional object on Object a two-dimensional surface (a Object sheet of paper or a computer Projector screen) using a representation system based on the projection Projector technique, which considers DOP views of an object from Projection plane Projection plane various imaginary planes. COP It is usual for engineering drawings to include a series of projections showing trimetric, when the angles different angles of the item, as between the three projections well as sections, views, and so on. are unequal; multi-view projection, when Most common projections more than one projection planes Parallel projection is a type of are used. projection in which the lines of the 3D oblique projection, when an object object never intersect with each other, is projected in a way that the face i.e. the lines always remain parallel to parallel to the picture plane is each other. It can be divided into: represented in an accurate manner, orthographic projection, which but the other faces are drawn on any is a way of projecting the object s convenient angle other than 90°. views on a 2D plane in which the Perspective projection which projection lines are perpendicular recalls the way in which the human to the surface. It can be: eye observes objects is a technique axonometric, when an object in which the lines of projection are is rotated along one or more of not parallel but converge at a point its axes relative to the plane of (called the vanishing point) placed on projection. It can be: the horizon line, and the vertical axes isometric, when the of the drawing are shown horizontal edges are drawn perpendicular to one another. In a on the 30° angle and perspective drawing, there can be verticals are perpendicular to more than one vanishing point (multithe horizontal base; point perspective), depending on the dimetric, when two of the alignment of the objects in a scene object faces are equally (i.e. buildings, roads, etc.). inclined;