Question 2
Fig. 1 shows a truncated hexagonal pyramid. Draw, full size and in first angle orthographic projection, the:
(a) given views;
(b) end view in the direction of arrow E;
(c) plan;
Observation
Many candidates attempted this question and their perfomance was not okay.
The soolution with the step-by-step requirement for the question, the lack of knowledge of which made the students not to perform well, is given below.
DRAWING THEA GIVEN VIEW OF A TRUNCATED HEXAGONAL PYRAMID,ITS FIRST ANGLE ORTHOGRAPHIC PROJECTION VIEWS AND THE SURFACE DEVELOPMENT OF ITS GIVEN SEAM
MAJOR REQUIREMENTS INVOLVED IN THE SKETCH OF THE REQUIRED ORTHOGRAPHIC VIEW
(b) PLAN
- Projecting down from the cut surface (top) to intercept the diagonals of the hexagon
- Projecting down from the cut surface (lower) to intercept the diagonals of the hexagon
- Joining the point to complete the plan
(c) END ELEVATION
- Projecting lines from the elevation and plan
- Drawing the end elevation E, F, G
(d) SURFACE DEVELOPMENT
- Drawing horizontal lines from the cut surface to touch the side AB
- Drawing the radial lines (5 no arcs) for development with centre A and using each point on AB as radius
- Stepping the base edges along the arc from B and joining to the apex
- Locating the points of the cut surfaces (top and lower) being the intersection of the arcs and the radiating lines from A
- Joining the points to obtain the surface development
- Neatness and quality of linework