Section Plane Section Plane Through ApexThrough Apex

Section PlaneSection PlaneThrough GeneratorsThrough Generators

Section Plane Parallel Section Plane Parallel to end generator.to end generator.

Section Plane Section Plane Parallel to Axis.Parallel to Axis.

TriangleTriangle EllipseEllipse

Para

bola

Para

bola

HyperbolaHyperbola

EllipseEllipse

Cylinder throughCylinder through generators.generators.

Sq. Pyramid through Sq. Pyramid through all slant edgesall slant edges

TrapeziumTrapezium

Typical Section Planes Typical Section Planes &&

Typical Shapes Typical Shapes Of Of

SectionsSections..

The plane is perpendicular to the top plane, therefore the section line is drawn in the Top View

It cuts the base at f and j

It cuts the edges at g and h

Join these points to o form the section face

A pentagonal pyramid (side of base = 50 mm and height = 100 mm) is resting on its base on the ground with axis parallel to frontal plane and perpendicular to the top plane. One of the sides of the base is closer and parallel to the frontal plane. A vertical section plane cuts the pyramid at a distance of 15 mm from the axis with section plane making an angle of 50o with FP. Draw the remaining part of the pyramid and the true shape of the cut section

50o

15

e’

a

re

a’ b’

co

c’m’

n

p

m

n’

p’

p1m1

n1

r1

100 The true shape of the section is drawn as an auxiliary view to the top view with the reference line parallel to the section plane

Section plane

50r’

b

d

d’

o’

T

F

A sphere of 75 mm diameter is cut by a section plane, perpendicular to the FP and inclined at 30o to the HP in such a way that the True Shape of the section is a circle of 50 mm dia. Draw its front view and sectional top view.

Sphere 75

50

30o

Draw the FV (circle with dia. 75 mm) and project the TV

Draw the cutting plane in FV such that it is 30o to the HP and makes a 50 mm chord on the FV circle

Draw concentric circles in the TV (center same as the center of the TV) and project them into the FV

Mark the points of intersection of the cutting plane with the concentric circles in the FV and project them into the TV

Join these points in the TV to get the sectional TV

T

F

A cube of 65 mm long edges has its vertical faces equally inclined to the FP. It is cut by a section plane, perpendicular to the FP so that the true shape of the section is a regular hexagon. Determine the inclination of the cutting plane with the HP and draw the sectional top view and true shape of the section

45o

45o

Section plane cuts the Mid points of edges of cube

Angle to be measured

65

T

F

PRIMARY AUXILIARY VIEW

(True shape of the section plane)

Section plane and reference line are parallel

a’, d’

d

a

f

e

d1

f’, e’

a1

b’, c’

f1

b1

c1

e1

b

c

Cutting plane is oblique

x

y

10

20

30

10

20

30

10 20 30

A

C

B

C

B

O1

O2

z

30

A

•Draw lines across the Top View (generator lines) starting from one corner of the plane upto the opposite side (AB).

•Project the intersection points between the generator lines and the side (AB) into the Front View

•Join these points with the corresponding corner C in the FV

•Project points of intersection of the section and the generator lines from the TV into the FV

•Two generator lines should be tangent to the section in the TV to get the width of the section in the FV

Generator lines

T

F

A cylinder, diameter of base 30 mm is standing on its base on ground and positioned in third quadrant. The position of center of upper base is O1 (25, 30, 25) and the center of the lower base is O2 (25, 30, 75). Points A (0,60,45), B(15, 5, 70) and C(65, 35, 35) lie on a plane that cuts the cylinder in two parts. Draw the two orthographic views of the cut portion of the cylinder. The coordinates of any point (x, y, z) represent distances measured from left profile plane, frontal plane and top plane respectively.