Transcript DEVELOPMENT OF SOLID FIGURES

SCHEME OF WORK FOR FIRST TERM.
WEEKS
1.
TOPICS
2.
3.
Development of solid figures – Definition, methods of construction (prism
and pyramid)
Development of surface of cylinder and cone.
Development of frustum of pyramids, prism, cylinder and cone.
4.
The true shapes of sections of pyramids, prism, cylinder and cone.
5.
6.
7.
8.
9.
Development of cylindrical and Triangular pipes and curves of
intersection.(interpenetration).
Sectional views.
Sectioning of mechanical components.
Screw threads.
Fasteners and locking devices and conventional representation.
10.
Revision / Examination.
LESSON OBJECTIVES:
Define the term development of solid
figures.
State the method of development
Draw the elevation of a pyramid and a
prism
Draw the development of a pyramid
Draw the development of a prism.
LESSON 1. DEVELOPMENT OF SOLID
FIGURES.
MEANING OF DEVELOPMENT
Development is the
method of unfolding or
unrolling a geometrical
shape into a plane shape.
METHODS OF DEVELOPMENT
The following are the different methods of
drawing the development of a solid figures.
1) Radial line method.
2) Parallel line method and
3) Triangulation method.
.Radial line method is used for drawing the
development of pyramid and cone.
. Parallel line method is used for drawing the
development of cylinders and prism.
. Triangulation method is used for drawing the
development of awkward or irregular shapes
.
DEVELOPMENT OF PRISM
A prism is named according to the
shape of its base. Its edges are
parallel to one another.
A line passing through the centre
of each end is called the axis.
The shapes of the prism are shown below.
SHAPES OF PRISM
The shapes of a prism according to
its base are shown below
70mm
40mm
Triangular prism
40mm
Square prism
40mm
Hexagonal prism
DEVELOPMENT OF PRISM
Development
70mm
40mm
1
2
3
4
5
6
7
DEVELOPMENT OF PYRAMID
A pyramid is named according to the shape of its
base. It has sloping sides meeting at a point
called the apex, which is vertically above the
centre of the base. They include;
1) Triangular pyramid.
2)Square pyramid and
3)Hexagonal pyramid.
These shapes are shown below.
SHAPES OF PYRAMIDS
70mm
50mm
Triangular pyramid
square pyramid
hexagonal pyramid
DRAWING OF DEVELOPMENT OF PYRAMID
70mm
RADIUS OF SLANT LINE
4
50mm
5
1
3
7
6
2
2
6
1
3
4
5
ASSIGNMENT
 The figure below shows, in first angle projection, the elevation and an incomplete
plan of a regular hexagonal oblique pyramid, truncated by a plane XX.
Draw ; (a)
(b)
(c)
the given elevation;
a complete plan;
the surface development making p-p the seam.