17/02/03Designed by Barry Forbes Graphic Communication Rectangular Pyramids

17/02/03 Designed by Barry Forbes Rectangular Pyramids n Square pyramids have a square base then sides that project upwards to one point.

17/02/03 Designed by Barry Forbes Rectangular Pyramids n The orthographic drawing of a square pyramid is shown on the next slide. n You should notice that the Elevation and End Elevation are both triangular in shape. n The plan has a square base with the 4 edges coming to one point in the centre.

Rectangular Pyramids ElevationEnd Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids n It as unlikely you will have to draw an uncut square pyramid in your exam. n The next slides show you how to draw a square pyramid with its top chopped off.

17/02/03 Designed by Barry Forbes Rectangular Pyramids n You will be shown how to draw the Plan, End Elevation and the development of the pyramid shown over the next few slides.

17/02/03 Designed by Barry Forbes Rectangular Pyramids The Elevation is given for you. You have to draw the Plan view. To make this easier we number each of the corners of the pyramid. The numbers on top are the corners at the front of the view. Next project the corners of the pyramid up vertically Elevation

17/02/03 Designed by Barry Forbes Rectangular Pyramids Mark on the depth given from the pictorial view. 1 4 Next project the corners of the pyramid up vertically. D 3 2 Elevation

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Next draw the edges of the pyramid. The edges go from one corner to the opposite corner. D 3 2 Elevation

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now project up the cut surfaces. D 3 2 Remember to number the corners of the plan to make this easier Elevation

Rectangular Pyramids 1 4 Joint up the points where you have just projected onto the corners. D 3 2 As it is a pyramid the edges are straight. Therefore, you should use a ruler to draw these lines Elevation

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 This is the plan view without the construction lines on it. D Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now we will draw the End Elevation Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Draw the 45° line from the top right hand corner of the Elevation You will have to construct where that point would be. Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now project the heights from the Elevation across the page Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now project the depths from the plan onto the 45° bounce line and down to the bottom of the End Elevation Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now darken in the outline of the End Elevation Elevation Plan

Rectangular Pyramids 1 4 This is the End Elevation shown without any construction lines showing Elevation Plan End Elevation

17/02/03 Designed by Barry Forbes Rectangular Pyramids n Now we will draw the development of the pyramid. n In order to do this we need to find the “true length” of the edges of the pyramid. n We don’t see the actual length of the edges because they slope away from us on both the Elevation and End Elevations.

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 We find the true length by using compasses to draw an arc from one corner to the other Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Then we project a vertical line down to the bottom of the Elevation Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now extend the edges of the Elevation to find where the top of the pyramid would be if it hadn’t been cut Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now draw a line from this constructed pyramid top to the bottom of the vertical line drawn This green line is the true length of the edge of the pyramid. Label it TL so you don’t get confused with any other lines. TL Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now set your compasses to this true length TL Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now draw an arc at this radius TL Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids 1 4 Now step out each of the lengths of the sides using your compass TL Elevation Plan

17/02/03 Designed by Barry Forbes Rectangular Pyramids Now use a ruler to draw lines from the centre of the arc to each of the lines you just stepped out on the arc

17/02/03 Designed by Barry Forbes Rectangular Pyramids Using a ruler, join the marks up

17/02/03 Designed by Barry Forbes Rectangular Pyramids Now using your compass, mark on the sizes of the cuts on the edges TL Project the cut along to the true length line then use the compass from the point of the pyramid. Use the edge numbers to make this easy. Elevation

17/02/03 Designed by Barry Forbes Rectangular Pyramids Now using your compass, mark on the sizes of the cuts on the edges TL Project the cut along to the true length line then use the compass from the point of the pyramid. Use the edge numbers to make this easy. Elevation

17/02/03 Designed by Barry Forbes Rectangular Pyramids Now using your ruler, join these marks up TL Use the edge numbers to make this easy. Elevation

17/02/03 Designed by Barry Forbes Rectangular Pyramids Elevation Plan Development