perspective conic section Is a system ofgraphical representation based on Projection of a three-di-mensional body on a bidimensional plane by means ofstraight lines that happen through a point. The result comes near to the vision that would be if Eye were placed in this point.

Terminology of the conical perspective

• Angle of incidence : The angle formed by a ray of light when falling on an object and by the surface of this object.

• Angle of reflection : The angle formed by a light ray and the surface of an object when the ray bounces in the object. He is equal to the angle of incidence.

• Point of view ( Eye or black Point ): It is the point from which is observed Image . of the spectator would be like Eye.

• visual Center : Also call Point of central flight (PFC), Front sight (PM) or main Point of flight (PFP), is the nearest point on the plane of the picture (it is seen more down) against the point of view. One is in the perpendicular of the point of view on the picture plane.

• optical Level - NOT : It is a complete horizontal circle around our eyes that we drew up turning the head or Horizon when we are concerning the sea.

• Line of the ground - ls : A line destined to themeasurement, passes level with the parallel ground and at the optical level (also called line of the land ). A measurementscale can be marked in her to project it to the CB or the pointsof flight (PP) and to try lateral measure-ments thus.

• Flat of the ground - PS : An imaginary, flat and horizontalextension of the ground on which we are stopped; one extends from our feet to the optical level in the plane of the picture.

• Line of the horizon - LH : In a mountainous landscape or of hills, it is the dividing line between the sky and the Earth and can be over the optical level (or underneath, in a perspective of three points).

• Line of distance - LD : Also denominated line of sight (LM), is the line that goes from the eye to the plane of the picture with which intersect in an angle of 90º. Its measurement allows to determine the range to which one is of the plane of the picture.

• Parallel of perspective : Also the term is used Parallel of flight . They are the lines seen like parallels in the plane, but that, in the perspective, seem to converge in the infinite in a point in the optical level.

• Flat of the picture - PC : Imaginary perpendicular to the line ofsight is a vertical plane, on which the drawing or the painting is sketched. The surface of our paper or the linen cloth can be considered. In order to include/understand it, it is enough with imagining a vertical leaf of a transparent glass to little distanceof us, through what our subject can be observed. What we see in the plane of the picture is determined by two factors: the height of the eye with respect to the line of the ground and the distance of the subject with respect to the eye. The distance between the eye and the subject usually is equal to the amplest dimension of our picture.

• Lines of drawing up : Lines that unite a point of a body with another one, or the tra-jectory of a shade in an object on the plane of the ground or by the object.

• Point of flight - PF : it is the place where all the straight parallels to a direction con-verge. They are points at optical level to either sides of the vision center towards which theparallel lines converge that move away of us and give the impression to disappear.

• Point of distance (PD) : It is a located auxiliary point on the line of earth, to an equal height to the separation of the planeof the picture to the point of view. It serves to find the points of flight of the perpendicular straight lines to one given.