ENGINEERING GRAPHICS
Semester:1
Vimal Samsingh R
Engineering Graphics
Lecture Notes
UNIT – 4
“SECTION OF SOLIDS ”
VSS
VSS
NEED FOR SECTIONING OF SOLIDS
SECTIONING A SOLID.
An object ( here a solid ) is cut by
some imaginary cutting plane
to understand internal details of that object.
The action of cutting is called
SECTIONING a solid
&
The plane of cutting is called
SECTION PLANE.
Two cutting actions means section planes are recommended.
OBSERVER
A) Section Plane perpendicular to Vp and inclined to Hp.
( This is a definition of an Aux. Inclined Plane i.e. A.I.P.)
NOTE:- This section plane appears
as a straight line in FV.
B) Section Plane perpendicular to Hp and inclined to Vp.
( This is a definition of an Aux. Vertical Plane i.e. A.V.P.)
NOTE:- This section plane appears
as a straight line in TV.
Remember:1. After launching a section plane
either in FV or TV, the part towards observer
is assumed to be removed.
2. As far as possible the smaller part is
assumed to be removed.
ASSUME
UPPER PART
REMOVED
(A)
(B)
ASSUME
LOWER PART
REMOVED
OBSERVER
Engineering Graphics
GE - 6152
TYPES FOR SECTIONAL VIEWS – SECTIONAL FRONT VIEW
Engineering Graphics
GE - 6152
TYPES FOR SECTIONAL VIEWS – SECTIONAL TOP VIEW
Engineering Graphics
GE - 6152
CROSS SECTION OF SOLIDS
TERMS & CONVENTIONS
Engineering Graphics
GE - 6152
METHOD OF HATCHING
ILLUSTRATION SHOWING
IMPORTANT TERMS
IN SECTIONING.
For TV
SECTION
PLANE
TRUE SHAPE
Of SECTION
x
y
Apparent Shape
of section
SECTION LINES
(450 to XY)
SECTIONAL T.V.
Typical Section Planes
&
Typical Shapes
Of
Sections.
Triangle Section Plane Ellipse
Section Plane
Through Generators
Through Apex
Section Plane Parallel
to end generator.
Ellipse
Cylinder through
generators.
Section PlaneHyperbola
Parallel to Axis.
Trapezium
Sq. Pyramid through
all slant edges
SECTIONAL VIEW – PARALLEL TO H.P AND PERPENDICULAR TO V.P
A cube of 40 mm sideis cut by a horizontal section plane, parallel to
H.P at a distance of 15 mm from the top end. Draw the sectional top
view and front view
SECTIONAL VIEW – INCLINED TO H.P AND PERPENDICULAR TO V.P
A square prism of base side 50 mm and height of axis 80 mm has its
base on H.P, it is cut by a section plane perpendicular to V.P and
inclined to H.P such that it passes through the two opposite corners of
the rectangular face in front. Draw the sectional Top View and Front
View. Find the angle of inclination of the section plane
SECTIONAL VIEW – PERPENDICULAR TO H.P AND INCLINED TO V.P
A square prism of base side 40 mm and height 70 mm is resting on its
rectangular face on the ground such that its axis is parallel to H.P &V.P,
it is cut by a section plane perpendicular to H.P &incllined to V.P at an
angle of 45° and passing through a point 10 mm from one of its ends.
Draw the sectional Front View and Top View
TRUE SHAPE OF A SECTION
PROCEDURE FOR TRUE SHAPE
EXAMPLE: TRUE SHAPE PROBLEM
A square prism of base side 50 mm and height of axis 80 mm has its
base on H.P, it is cut by a section plane perpendicular to V.P and
inclined to H.P such that it passes through the two opposite corners of
the rectangular face in front. Draw the sectional Top View and Front
View and true shape of the section
Problem 1: A pentagonal prism , 30 mm base side & 50 mm axis
is standing on Hp on it’s base whose one side is perpendicular to Vp.
It is cut by a section plane 450 inclined to Hp, through mid point of axis.
Draw Fv, sec.Tv & sec. Side view. Also draw true shape of section and
Development of surface of remaining solid.
C
B
D
A
Y1
Solution Steps:for sectional views:
Draw three views of standing prism.
Locate sec.plane in Fv as described.
Project points where edges are getting
Cut on Tv & Sv as shown in illustration.
Join those points in sequence and show
Section lines in it.
Make remaining part of solid dark.
E
d”
X1
b”
e”
a”
X
e
d
a
c
b
c”
Y
For True Shape:
Draw x1y1 // to sec. plane
Draw projectors on it from
cut points.
Mark distances of points
of Sectioned part from Tv,
on above projectors from
x1y1 and join in sequence.
Draw section lines in it.
It is required true shape.
Problem 2: A cone, 50 mm base diameter and 70 mm axis is
standing on it’s base on Hp. It cut by a section plane 450 inclined
to Hp through base end of end generator.Draw projections,
sectional views, true shape of section and development of surfaces
of remaining solid.
Y1
Solution Steps:for sectional views:
Draw three views of standing cone.
Locate sec.plane in Fv as described.
Project points where generators are
getting Cut on Tv & Sv as shown in
illustration.Join those points in
sequence and show Section lines in it.
Make remaining part of solid dark.
SECTIONAL S.V
o’
DEVELOPMENT
X1
X
For True Shape:
Draw x1y1 // to sec. plane
Draw projectors on it from
cut points.
Mark distances of points
of Sectioned part from Tv,
on above projectors from
x1y1 and join in sequence.
Draw section lines in it.
It is required true shape.
a’ h’ b’
c’ g’
h
g
f’ d’
e’
f
a
e
bSECTIONAL T.V d
c
g” h”f”
a”e”
b”d” c”
Y