Isometric Projection 3

Isometric Projection - 3


Dear Students,

We have learnt some basic concepts of Isometric Projection in the last two classes and solved some problems pertaining to planar figures. Now we shall learn to make isometric projection of frustums.

A few examples of frustums
                    
     
Figure 1: Frustum of a Square Pyramid     




          


Figure 2: Frustum of a Hexagonal Pyramid


1. What is a frustum?   

A frustum is a truncated part of a cone or a pyramid. In other words the portion of a cone or a pyramid which remains after the upper part has been cut off by a sectioning plane parallel to its base. Refer figures 1 and 2 above.

2. How to draw the isometric projection of a frustum?

We follow few basic steps as enlisted below:

a). Draw a helping figure: You will draw both the face and the base of a frustum of a pyramid i.e. a small and a big triangle, square, pentagon or a hexagon. Enclose the figure within a box. Mention the title 'HELPING FIGURE' within two parallel lines 6 mm apart.

b). Draw 30-30 axis: Here you must draw the box of the base of the frustum. Draw the tiangle/square, pentagon, hexagon inside the box. Mark its centre and then raise the centre equal to the height of the frustum (isometric length).

c). Draw 30-30 cross: Here you draw the box of the top face of the frustum using the half- half concept as learnt in class 11.

d). Join the visible edges (between the top face and the base) of the frustum         

e). Mention titles, dimensions, indicate the direction of viewing.




Exercise - 3 : Isometric Projection of Frustums 

Instructions:
a. Show direction of viewing, mark its centre and mention dimensions in all the questions.
b. Solve these questions in your drawing file
c. Please take a picture of your answers and post them in the EG Group.


Q 1 





Q 2





Q 3