Chapter #2 ORTHOGRAPHIC PROJECTIONS

ENGINEERING DRAWING Drawing Classification of drawing Engineering drawing/definitions/applications Projection/definition/principle Orthographic projections/definition/principle Principal Planes of projections Principal views Position of an object in different quadrants Angle of projection Concept of profile views

DRAWING Graphical representation of an object is called drawing. Representing an object using lines, arcs, circles, etc which gives some meaning to the reader is called drawing. Universal language of Engineers. Graphic language of Engineers. Mode of communication through sketches is called Graphic language.

CLASSIFICATION OF DRAWING

ENGINEERING DRAWING Drawings drawn by an engineer, using engineering instruments, engineering concepts, engineering principles, engineering processes etc used only for engineering applications.

PRINCIPLE OF PROJECTION

PRINCIPLE OF PROJECTION WHAT IS THE NEED ?

GEOMETRICAL OBJECTS Dimensionless objects One dimensional objects Two dimensional objects Three dimensional objects

EXAMPLES POINT IS A DIMENSIONLESS OBJECT LINE IS A ONE DIMENSIONAL OBJECT PLANE/ LAMINA IS A TWO DIMENSIONAL OBJECT SOLID IS A THREE DIMENSIONAL OBJECT

ACTUAL DRAWINGS REQUIRED FOR FABRICATION/ CONSTRUCTION OR MANUFACTUREING

PROJECTION Principles of Projection invented by French Mathematician, GASPARD MONGE in 1800. Today it has become an indispensable tool of an engineer to transform his ideas into reality. The word projection is a latin word, meaning “to throw forward”

PRINCIPLE OF PROJECTION FILM PROJECTOR RAY OF LIGHT VIEW LIGHT SOURCE RAY OF LIGHT OBJECT LENS PLANE OF PROJECTION PRINCIPLE OF PROJECTION SCREEN

PRINCIPLE OF PROJECTION PLANE OF PROJECTION RAYS OF SIGHT MEAN POSITION OBJECT GROUND

ORTHOGRAPHIC PROJECTION OBJECT PROJECTORS LIGHT RAYS PLANE OF PROJECTION LIGHT RAYS SOURCE  LIGHT RAYS PROJECTORS

ORTHOGRAPHIC PROJECTION Orthographic projection is a means of representing a three-dimensional (3D) object in two dimensions (2D). It uses multiple views of the object.

PRINCIPAL PLANES OF PROJECTIONS VERTICAL PLANE [VP] HORIZONTAL PLANE [HP] PROFILE PLANES [PP] a) LEFT PROFILE PLANE [LPP] b) RIGHT PROFILE PLANE [RPP]

PRINCIPAL VIEWS FRONT VIEW [ELEVATION] TOP VIEW [PLAN] PROFILE VIEWS [END VIEWS] a. RIGHT END VIEW b. LEFT END VIEW

POSITIONS OF OBJECT IN DIFFERENT QUADRANTS VERTICAL PLANE HORIZONTAL PLANE

VP II QUADRANT I QUADRANT OBSERVER DIRECTION HP HP III QUADRANT I V QUADRANT VP

VP II QUADRANT I QUADRANT ABOVE HP INFRONT OF VP ABOVE HP BEHIND VP OBSERVER DIRECTION HP HP BELOW HP INFRONT OF VP BELOW HP BEHIND VP III QUADRANT I V QUADRANT VP

VP II QUADRANT I QUADRANT ABOVE HP INFRONT OF VP INFRONT OF RPP INFRONT OF LPP ABOVE HP BEHIND VP BEHIND RPP BEHIND LPP OBSERVER DIRECTION HP HP BELOW HP INFRONT OF VP INFRONT OF RPP INFRONT OF LPP BELOW HP BEHIND VP BEHIND RPP BEHIND LPP III QUADRANT I V QUADRANT VP

RPP LPP VP HP LEFT VIEW RIGHTVIEW RIGHT VIEW IS PROJECTED ON LPP LEFT VIEW IS PROJECTED ON RPP OBJECT IS ALWAYS INFRONT OF VP, RPP,LPP. POINT IS ALWAYS LIES BETWEEN OBSERVER AND PLANE 1ST QUADRANT

RPP LPP VP HP LEFT VIEW RIGHTVIEW RIGHT VIEW IS PROJECTED ON RPP LEFT VIEW IS PROJECTED ON LPP POINT IS ALWAYS BEHIND VP, RPP,LPP. PLANE ALWAYS LIES BETWEEN OBSERVER AND THE POINT FRONT VIEW 2ND QUADRANT

RPP LPP VP HP LEFT VIEW RIGHTVIEW RIGHT VIEW IS PROJECTED ON RPP LEFT VIEW IS PROJECTED ON LPP POINT ALWAYS BEHIND VP, RPP,LPP. PLANE ALWAYS LIES BETWEEN OBSERVER AND THE POINT FRONT VIEW 3RD QUADRANT

4TH QUADRANT RIGHTVIEW VP RPP HP LEFT VIEW LPP OBJECT IS ALWAYS INFRONT OF VP, RPP,LPP. POINT ALWAYS LIES BETWEEN OBSERVER AND PLANE RIGHT VIEW IS PROJECTED ON LPP LEFT VIEW IS PROJECTED ON RPP

FIRST ANGLE PROJECTION

VP I QUADRANT II QUADRANT F V OBSERVER DIRECTION HP TV HP III QUADRANT I V QUADRANT VP

VP I QUADRANT II QUADRANT F V HP OBSERVER DIRECTION HP TV III QUADRANT I V QUADRANT VP

VP I QUADRANT II QUADRANT F V OBSERVER DIRECTION HP TV HP III QUADRANT I V QUADRANT VP

VP I QUADRANT II QUADRANT F V OBSERVER DIRECTION HP TV III QUADRANT I V QUADRANT VP HP

CONVENTION FOR FIRST ANGLE FRONT VIEW VP X Y HP TOP VIEW

SECOND ANGLE PROJECTION

II QUADRANT VP I QUADRANT F V OBSERVER DIRECTION HP TV HP III QUADRANT I V QUADRANT VP

CONVENTION FOR FIRST ANGLE TV FV HP VP X Y

THIRD ANGLE PROJECTION

VP I QUADRANT II QUADRANT OBSERVER DIRECTION HP TV HP F V III QUADRANT I V QUADRANT VP

CONVENTION FOR FIRST ANGLE TV HP X Y VP FV

FOURTH ANGLE PROJECTION

VP I QUADRANT II QUADRANT OBSERVER DIRECTION HP TV HP F V III QUADRANT I V QUADRANT VP

CONVENTION FOR FIRST ANGLE X Y VP HP FV TV

CONCEPT OF PROFILE VIEWS

PROFILE VIEWS IN FIRST ANGLE PROJECTION Right end view projected on left profile plane. Left end view projected on right profile plane.

PROFILE VIEWS IN THIRD ANGLE PROJECTION Right end view projected on RIGHT profile plane. Left end view projected on LEFT profile plane.