Johnstone High School Graphic Communication Rectangular Pyramids Technology Department

Rectangular Pyramids Square pyramids have a square base then sides that project upwards to one point.

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

Rectangular Pyramids Plan Elevation End Elevation

Rectangular Pyramids It as unlikely you will have to draw an uncut square pyramid in your exam. The next slides show you how to draw a square pyramid with its top chopped off.

Rectangular Pyramids You will be shown how to draw the Plan, End Elevation and the development of the pyramid shown over the next few slides.

Rectangular Pyramids 4 3 Next project the corners of the base up vertically. The Elevation is given, draw the Plan. To make this easier we number each of the corners of the pyramid. Complete the plan base. Complete the pyramid by connecting the corners 1 2 Number the corners of the Plan. The numbers on top are the corners at the front of the view. Project up the corners of the cut surface. 1 Connect the points of the cut surface on the Plan.. 2 Elevation 4 3

Rectangular Pyramids 4 3 The Plan should now be as shown if lines were firmed in. 1 2 1 2 Elevation 4 3

Rectangular Pyramids 4 3 Project the Heights from the Elevation and widths from the Plan to construct the End Elevation. Connect the points on the cut surface. 1 2 Firm in the Outline. Number the points on the base. Project the cut surface from the Elevation 1 Elevation 2 2 3 4 3 1 4

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

Rectangular Pyramids 4 3 Rotate a corner about the apex on the plan to meet a horizontal line from the apex. Project down to the ground line of the Elevation 1 2 1 Elevation 2 2 3 4 3 1 4

Rectangular Pyramids 4 3 Connect the point to the apex. This is the True length of the sloping side. Indicate that it is the True Length Line. 1 2 T/L 1 Elevation 2 2 3 4 3 1 4

Rectangular Pyramids 4 3 Using a compass, rotate the length of the True Length line about a point. Connect the centre of the arc to an end of the arc. 1 2 1 2 2 3 Elevation 3 1 4 4

Rectangular Pyramids The Elevation is given for you. You have to draw the Plan view. Rectangular Pyramids 4 3 1 2 1 2 2 3 Elevation 3 1 4 4

Rectangular Pyramids 1 4 3 Using a compass, mark the length of the base along the arc 4 times. 4 Connect these points to the apex then each other in turn. 1 2 3 Number the points with a short edge on the outside. 2 1 2 2 3 Elevation 4 3 1 4 1

Rectangular Pyramids 1 4 3 On the Elevation, project the cut surface horizontally to the True Length Line. 4 Transfer the true lengths of the cut surface to the development. 1 2 3 2 1 2 3 Elevation 2 4 3 1 4 1

Rectangular Pyramids Connect the points. Then firm in. 1 3 4 4 1 2 3 2 Elevation 2 4 3 1 4 1

PowerPoint Presentation. 2003