Detailed step by step explanation

1. Isometric View of a Truncated
Pentagonal Pyramid
Drawing Steps By:
SUBIN B MARKOSE
Assistant Professor

2. Question
• A pentagonal pyramid of base side 30 mm and axis
height 65 mm is resting on HP on its base with a
side of base perpendicular to VP. It is cut by a plane
inclined at 30 degrees to HP and perpendicular to
VP, passing through a point on axis at 30 mm from
the apex. Draw the isometric view of the remaining
portion of the pyramid.

3. Step 1
• Draw the front and top view of the pyramid in the
specified position.
• Mark the dimensions.
• Name the solid correctly.

5. Step 2
• Mark the point on axis through which cutting plane
is passing.
• Mark the dimension.
• No separate name is given to that point.

7. Step 3
• Draw the cutting plane inclined at 30 degrees to HP.
• The cutting plane cuts the edges of the pyramid at
the points a,b,c,d & e.
• Mark them clearly on front and top view.

9. Step 4
• Join the cutting points on top view and shade the
region.
• Now sectional top view is complete.

11. Step 5
• Enclose the top view inside a box.
• Name the box as 1-2-3-4.
• Draw the isometric axes and plot the point '1'.
• Similarly plot all other points of the box 2,3 & 4 on
the isometric axes and complete the box.

15. Step 6
• The base of the pyramid is a pentagon.
• Plot all the corners of the pentagon on the
isometric view.
• This is done by plotting the points from the top
view and marking them correctly on to the
isometric axes.
• Distance of corners of pentagon should be taken
correctly from top view and plot them on the
correct edges.

17. Step 7
• Now we are going to plot the cutting points a,b,c,d
& e on the isometric view.
• Let us start with point 'a'.
• Focus on point '5 ' on top view.
• Point '5' is obtained by drawing a horizontal line
through point 'a'.
• Point '5' is on edge 4-1.

19. Step 8
• Plot point '5' on to isometric axis 4-1.

21. Step 9
• Draw a line through point '5' parallel to edge 1-2 .
• Mark the distance 5-a from top view on the
parallel line as shown.
• Please look carefully as construction lines are
drawn very lightly.

24. Step 10
• We are going to plot point 'a' on the isometric
view.
• Point 'a' is at a particular height above XY line
which can be taken from front view.
• Measure the height of point 'a' from XY line and
plot it on isometric view.
• Study the coming slides thoroughly and
draw.

27. Step 11
• Repeat the same steps for plotting other points
b,c,d,& e.
• Draw a horizontal line through point 'b' and
mark point '6' on top view.
• From top view, plot 6 onto isometric view.

30. Step 12
• Point 'b' is also at the same height as that of point
'a' which can be measured from front view.
• Plot 'b' at the height as shown.
• It is drawn very lightly so look carefully.

32. Step 13
• For plotting points 'c & 'd', draw two horizontal
lines and mark points '7' & '8'.
• Repeat the same steps we used to plot the points
'a' & 'b'.
• Follow the images thoroughly.

35. Step 14
• Now the last point 'e' has to be plotted.
• It is much easier and refer the slides for clarity.
• Repeating same steps as before.

38. Step 15
• Now we have plotted all the cutting points on the
isometric view.
• Join them to get the top face of the pyramid.

40. Step 16
• Join the edges of the pyramid looking at the front
and top views.
• Highlight the truncated pyramid as shown.

43. Comments
• Feel free to rectify doubts.
• Draw lightly.
• Here you have to take measurements from both
top and front views to complete the isometric view.
• Naming the cutting points is very important.
• Draw very carefully.

44. • End of presentation...