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 verti

1
Typical Section Planes Typical Shapes Of
Sections.
Section Plane Through Generators
Ellipse
Triangle
Section Plane Through Apex
Parabola
Section Plane Parallel to Axis.
Section Plane Parallel to end generator.
Hyperbola
Ellipse
Trapezium
Cylinder through generators.
Sq. Pyramid through all slant edges
2
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
d
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
Section plane
15
r
e
c
p
o
n
m
T
a
b
50o
o
F
p1
n1
r1
n
p
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
m1
m
e
b
c
r
a
d
50
3
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.
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
30o
F
f50
Sphere f75
4
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
e
PRIMARY AUXILIARY VIEW (True shape of the section
plane)
d
c
Angle to be measured
d1
45o
45o
e1
a1
a
b
T
f
F
c1
a, d
f1
b1
Section plane cuts the Mid points of edges of cube
65
f, e
Section plane and reference line are parallel
b, c
5
Cutting plane is oblique
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.
y
A
C
30

• 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

20
T
10
B
x
10
20
30
10
F
O1
20
30
30
C
A
B
O2
z