Department
of
Technological
Education
Graphic Communication
Nairn Academy
Department of Technological Education
Cut Square Pyramid - Question
The given views show the
Front Elevation and
unfinished Plan of a cut
square pyramid.
Draw the following views :The completed Plan
End Elevation
Surface Development of
sides
True Shape of cut
Department of Technological Education
Finding Position of End Elevation
Using the Plan and the
Front Elevation project the
position of the End
Elevation and show the
slope of the sides.
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Number each of the points
in each view.
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Department of Technological Education
Finding Position of cut on End Elevation
Project from the Front
Elevation to find the cut
surface on the End
Elevation.
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2
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3
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Darken the outlines on the
End Elevation.
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Department of Technological Education
Finding Position of cut on Plan
Project from the Front
Elevation to find the cut
surface on the Plan.
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2
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Darken the outlines on the
Plan.
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1 /2
Department of Technological Education
Finding True Length of pyramid corner
Before the Development can
be drawn it is necessary to
find out the True Length of
the corner of the pyramid so
that accurate sizes for the
development and the cut
points can be found
Draw a curve on the plan with
the centre being located at the
centre of the pyramid, the
radius being measured at one
of the corners, and the end
point of the curve being the
centre line.
Project the point found onto
the Elevation baseline and
draw a generator to the apex
of the pyramid.
Project the cut points from the
elevation onto this True Length
line.
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Department of Technological Education
Drawing the outline of the Development
Indicate where the
development is going to be
placed, and then draw the
first generator to indicate one
corner of the pyramid.
Measure the length of the
corner of the pyramid using
the True Length line and draw
a curve on the Development at
this size.
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2
1
2
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3
Step off the length of each of
the sides of the pyramid onto
the Development.
3
Draw generators to each of
these points to indicate the
fold lines
Number each of the points.
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Department of Technological Education
Drawing the cut on the Development
Step off from the True
Length line the distance
from the apex of the
pyramid to each cut point
and transfer these sizes to
the correct generators on
the Development.
Join each of the points to
show the developed shape of
the cut. Also add the flat
edges to the base of the
pyramid on the
Development.
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2
1
2
4
3
3
Darken the outlines on the
Development.
Add the fold lines to
complete the view.
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Department of Technological Education
Drawing the True Shape
To find the True Shape,
project the cut points away
from the Front Elevation at
right angles to the cut.
Draw a datum line on the
True Shape parallel to the
cut line of the Front
Elevation and at right angles
to the lines just projected.
Use the centre line of the
plan as a datum line.
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2
1
2
4
3
Measure the vertical
distances from the datum to
each of the cut points on the
plan. Transfer each of these
sizes on to the True Shape.
Join each of the points found
to produce the True Shape.
Complete the view by
darkening the outlines.
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4
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PowerPoint Presentation produced by John McRae, Nairn Academy 2003