Projection of Pyramid

Sample Problem 1:
A tetrahedron of 40 mm side rests with one of its edges on HP and perpendicular to VP. The triangular face containing that edge is inclined at 30º to HP. Draw its projection.

Steps for Projection of Pyramid:

Simple Position:
1. Top View:
Draw the top view of the tetrahedron resting on HP on one of its faces with an edge of the face perpendicular to VP. It is an equilateral triangle of side 40 mm with one side perpendicular to XY.

Locate the center o by drawing the bisectors of the included angles of the triangle. Join o with a,b and c.

2. Front View:

Line co representing one of the edges is parallel to XY in top view. Hence it is parallel to VP and its front view shows true length.

c’ as center and true length (40 mm) as radius draw an arc to meet the projector through o at o’ . join a’ & c’ with o’. Complete the front view.

Second Position

3. Tilt the front view about a’ such that face ABC represented by a'(b’)c’ in the front view is inclined at 30º to XY.

4. Draw the second front and top views.

Sample Problem 2:
A right pentagonal pyramid of base side 20 mm and altitude 60 mm rests on one of its edges of the base in HP. the base being lifted up until the highest corner in it is 20 mm above HP. Draw the projections of the pyramid when the edge on which it rests is made perpendicular to VP.(UQ)

Steps for Projection of Pyramid:

1.Draw the top view with an edge of the base ⊥r to XY. Project corresponding front view.

2. Draw a locus line 20 mm above XY. Fix the base edge point r’ on xy.

Draw an arc with r’ as center and r’ p’ as radius to cut the locus line at p’. Complete second front view.

Project the corresponding second top view. Mark (s1)& (r1).

Video Material for Projection of Pyramid



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