ENGINEERING GRAPHICS IENGINEERING GRAPHICS I

Prof. N. P. Jadhav Prof. S. A. Ladkat

Presented by

Department of Mechanical EngineeringSinhgad Academy of Engineering, Pune

FIRST YEAR ENGINEERINGFIRST YEAR ENGINEERINGFIRST YEAR ENGINEERINGFIRST YEAR ENGINEERING

Unit 1 Curves used in Engineering Practice

SYLLABUS

Unit 2 Orthographic Projections

Unit 3 Auxillary Projections

Unit 4 Isometric Projections

Unit 5 Interpretation of Given Views/Missing

ViewsUnit 6 Freehand Sketching

Weightage for each Unit

SECTION I

Unit 1) Engineering Curves 15

Unit 2) Orthographic Projections 20

Unit 3) Auxillary Projections 15

SECTION II

Unit 4) Isometric Projections 20

Unit 5) Missing Views 20

Unit 6) Freehand Sketching 10

NATURE OF QUESTION PAPER

SECTION I

Q 1) Engineering Curves 15OR

Q 2) Engineering Curves 15

Q 3) Orthographic Projections 20

Q 4) Orthographic Projections 20OR

Q 5) Auxillary Projections 15

Q 5) Auxillary Projections 15OR

NATURE OF QUESTION PAPER

SECTION II

Q 7) Isometric Projections 20OR

Q 8) Isometric Projections 20

Q 9) Missing Views 20

Q 10) Missing Views 20OR

Q 11) Freehand Sketching 10

Q 12) Freehand Sketching 10OR

TERM WORK

Sheet No. 1 Engineering CurvesTo draw any four curves.

Sheet No. 2 Orthographic Views To draw two principal views, one sectional

views for two objects

Sheet No. 3 Auxillary ViewsTo draw auxillary views from the given views for any two objects.

Sheet No. 4 Isometric ViewsTwo problems

Sheet No. 5 Missing ViewsTwo problems

BOOKS

1 N.D. Bhatt, Elementary Engineering Drawing

2 P.S. Gill, Engineering Graphics

3 D. N. Johle, Engineering Drawing

4 Engineering Graphics by M. L. Dabhade.

ORTHOGRAPHICS PROJECTIONSORTHOGRAPHICS PROJECTIONSORTHOGRAPHICS PROJECTIONSORTHOGRAPHICS PROJECTIONS

Contents :

* Types of Drawing* Theory of projections* Types of projections* Perceptive projections* Oblique projections* Isometric projections* Orthographic projections* Quadrant systems* Principal planes* Glass box concept* First angle projection method

Contents :

* Principal projections* Conversion of pictorial view in to orthographic views

* Problems

Types of Drawings

Nature Drawings ( landscape, scenery etc.)

Geographical Drawings ( maps etc.)

Botanical Drawings ( plants, flowers etc.)

Zoological Drawings (creatures, animals etc.)

Portraits ( human faces,

expressions etc.)

Engineering Drawings

Machine component DrawingsBuilding Related Drawings

Orthographic Projections(FV,TV & SV.-Mech.Engg. terms)(Plan, Elevation- Civil Engg.terms)

(Working Drawings 2-D type)

Isometric ( Mech.Engg.Term.)or Perspective(Civil Engg.Term)

(Actual Object Drawing 3-D)

TorchLight Rays Ball

(Observer)(Projectors)

(Object)

(Plane of Projection)

Theory of Projection

Shadow

(Projection)

Wall

Projection means “To throw Forward”.

In this Object are being thrown (projected) forward in the form of Projection.

Torch Ball Shadow Wall

Torch Observer

Ball Object

Shadow Projection

Wall Plane of Projection

Types of Projection

Orthographic ProjectionOrthographic Projection

Oblique Projection

Perspective Projection

Isometric Projection

Perspective Projection

* Observer is at finite distance.

* Rays or Projectors are converging at observer’s eye.

* It does not provides exact size and shape of object.

ObjectPlane of p

rojection

Projection

Station point

Orthographic Projection

* Assume that observer is at infinite distance and rays or Projection lines are Parallel to each other and Perpendicular to the Plane of Projection.

* ORTHO means Perpendicular.

* Since the projectors are perpendicular to the plane of projection, the view is called Orthographic View and the projection method is called Orthographic projection.

Latin Origin

Orthographic Projection

* Orthographic projection is a two dimensional projection method.

* FV : Length and height of Object

* As projectors are Parallel to each other, the size of Orthographic View of an object is equal to the actual size of an object.

FOR F.V.

90 o90 o

Oblique Projection

* Observer is at infinite distance.* Rays or Projectors are Parallel to each other.

* Rays or Projectors are not Perpendicular to the Plane of projection. (i.e. projectors are inclined to the plane of projection i.e. oblique)

Φ ≠ 90o

Object

Projectors

Plane of projection

shadow

Isometric Projection

* Observer is at infinite distance.

* Rays or Projectors are parallel to each other & perpendicular to the plane of projection.

* All faces of the object are equally inclined to the planes of projection.

* All faces of the object are visible in a single view.

Quadrant system

1ST Quad.2nd Quad.

3rd Quad. 4th Quad.

VP

HPObserver

X

Y

Quadrant system

QuadrantQuadrant Observer; Object; Plane Observer; Object; Plane positionspositions

Position of object w.r.t. planes Position of object w.r.t. planes of projectionof projection

First Observer – Object – Plane Above HP, In Front of VP

Second Observer – Plane – Object Above HP, Behind VP

Third Observer – Plane – Object Below HP, Behind VP

Fourth Observer – Object – Plane Below HP, In Front of VP

TYPES

HORIZONTAL PLANE (H P)

PROFILE PLANE (PP)

VERTICAL PLANE (VP)

PRINCIPAL PLANES

Glass box concept

V. P.P. P.

H. P.

1st angle projection method

Projectors are perpendicular to respective Reference Plane and are also Parallel to each others

NOTE

F.V.

T.V.

L.H.S.V.

1st angle projection method

F.V.

T.V.

L.H.S.V.

NOTENOTE

Horizontal plane is rotated clockwise from the left and profile plane is rotated anticlockwise from the top so that all the three principal planes lies in a single plane .

V.P.

H.P.

P.P.

F V

T V

L H S V

V.P.

H.P.

P.P.

F V

T V

L H S V

F V

T V

L H S VX Y

X1

Y1

Important points for first angle projection methodImportant points for first angle projection method

* Object is situated in the First Quadrant.

* Object lies between the observer & Principal Planes.

* Orthographic projection of an object obtained on the VP is FV & always lies above the X-Y line.

* Orthographic projection of an object obtained on the HP is TV & always lies below the X-Y line.

* Orthographic projection of an object obtained on the PP is SV & always lies on the side of FV & above the X-Y line.

* RHSV is drawn on the left side of FV.* LHSV is drawn on the right side of FV.

PRINCIPAL PROJECTIONS

Direction of Direction of SightSight

Plane of ProjectionPlane of Projection Name of ProjectionName of Projection

Front Vertical Plane (VP) FV or ElevationTop Horizontal Plane

(HP)TV or Plan

Right Hand

Profile Plane (PP) RHSV

Left Hand Profile Plane (PP) LHSV

Conversion of Pictorial view into Orthographic Views

Study of the object.

Find the overall size of object i.e. Length, Width & Height.

Draw blocks for F.V. (L x H), T.V. (L x W) & S.V. (W x H) in their respective position according

to the method of projection.

Take suitable distance of above blocks from reference lines (X-Y & X1-Y1).

In respective block, first draw the contour of the view followed by visible edges & at the end draw the hidden details.

After drawing all views give all necessary dimensions (specify major dimension).

Draw the view first which gives maximum visibility & which is simple to draw.

IMPORANT POINTS

If line is parallel to both Vertical Plane & Horizontal Plane then Front View & Top View of the line always gives True Length on respective plane.

TL TL

CASE 1 :

TL

If line is perpendicular to one of the reference plane (say ┴ to H.P.) then the view obtained is always Point view.

IMPORANT POINTS

If Plane is Parallel to V.P. then in F.V. we get True Shape of Plane while in T.V. only Line View is observed.

TS

CASE 2 :

If Plane is Parallel to H.P. then in T.V. we get True Shape of Plane while in F.V. only Line View is observed.

TS

X Y

L.H.S.V.FOR L H S V

FOR T V

ORTHOGRAPHIC PROJECTIONS

FOR F V

F V

T V

X1

Y1

PROBLEM 1

X Y

FOR L H S V

FOR T V

FOR F V

X1

Y1

F V

T V

L.H.S.V.

PROBLEM 2

ORTHOGRAPHIC PROJECTIONS

PROBLEM 3

X

Length = 63 mm

Height = 37 + 10 = 47 mm

Width = 40 mm

F.V. = L x H = 63 x 47

T.V. = L x W = 63 x 40

S.V. = W x H = 40 x 47

X Y

X1

Y1X

PROBLEM 4

X

Length = 27+20+27 = 74 mmHeight = 8+8+25 = 41 mmWidth = 41 mm

F.V. = L x H = 74 x 41

T.V. = L x W = 74 x 41

S.V. = W x H = 41 x 41

X Y

X1

Y1X

Problem5 - Pictorial view of the object is as shown in fig. draw 1) Front View in direction of Arrow X

2) Top View 3) Right hand side view.

XX

H =

44

H =

44

L = 86W = 44

W =

44

T.V

F.VR.H.S.V.

L = 86

X

X1

Y

Y1

X Y

X1

Y1