Square%20Pyramid%20(cut)

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Square Pyramid (cut)
Graphic Communication
Department of Technological Education
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Cut Square Pyramid - Problem
Department of Technological Education

• 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 surface

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Finding Position of End Elevation
Department of Technological Education

• 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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2

• Number each of the points in each view.

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4
1
/4
/3
2
3
/4
/2
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Finding Position of cut on End Elevation
Department of Technological Education

• Project from the Front Elevation to find the cut
  surface on the End Elevation.

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2

• Darken the outlines on the End Elevation.

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4
1
/4
2
3
/2
1
/3
/4
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Finding Position of cut on Plan
Department of Technological Education

• Project from the Front Elevation to find the cut
  surface on the Plan.

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2

• Darken the outlines on the Plan.

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4
1
/4
2
/3
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Finding True Length of pyramid corner
Department of Technological Education

• 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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Drawing the outline of the Development
Department of Technological Education

• Indicate where the development is going to be
  placed, and then draw the first generator to
  indicate one corner of the pyramid.

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• 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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• 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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Drawing the cut on the Development
Department of Technological Education
Alternative Layout

• 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.

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2

• 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.

3

• Darken the outlines on the Development.

• Add the fold lines to complete the view.

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1
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Drawing the True Shape
Department of Technological Education

• To find the True Shape, project the cut points
  away from the Front Elevation at right angles to
  the cut.

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2

• 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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4

• 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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