Graphic Communication True Shapes The Cone CDT Department

True Shape This type of drawing is asked to be drawn as part of a cut, prism, pyramid, cylinder or cone. It shows the actual shape of a sloping surface. They can be quite confusing but are not as hard to produce as they look.

True Shape As there are other slides and presentations depicting how to draw cut prisms, pyramids, cylinders and cones we are not going to show you how to do these things in this slideshow. Instead we will focus on producing the true shape.

True Shape We will assume that the drawing is as shown. 1 2 1 1 1 1 2 2 9 3 8 4 7 5 6 9 8 7 6 5 4 3 6 5 4 3 2 1 1 2 1 1 1 1 2 1 2 7 8 9 1 1 1

True Shape 1 2 From the Elevation project at 90º the end points which the cut surface intersects with the generator lines. 1 1 1 1 2 9 3 8 4 7 5 Draw a datum line for the true shape parallel to the cut surface. 6 Project the other points that intersect the cut surface. 9 8 7 6 5 4 3 6 5 4 3 2 1 1 2 1 1 1 1 2 1 2 7 8 9 1 1 1

True Shape Number the lines. 1 2 Number the lines. 1 1 1 8 7 9 11 6 10 12 5 1 2 1 4 2 9 3 3 On the Plan, draw vertical lines from the intersection between the generator lines and the curve to the centre line of the circle. 8 4 7 5 6 9 8 7 6 5 4 3 6 5 4 3 2 1 1 2 1 1 1 1 2 1 2 7 8 9 1 1 1

True Shape 1 2 Using a compass take the distances and put them on either side of the datum line of the true shape. 1 1 1 8 7 9 10 11 6 12 5 1 2 1 4 2 9 3 3 8 4 7 5 Connect up the points to show the true shape of the cut surface. 6 9 8 7 6 5 4 3 6 5 4 3 2 1 1 2 1 1 1 1 2 1 2 7 8 9 1 1 1

True Shape - Cones The final result.