Engineering Graphics – Projection of Solid

Engineering Graphics: Understanding the Projection of Solids

When it comes to engineering graphics, projection of solids is a fundamental skill—and it’s more than just a technical requirement. Imagine trying to explain a 3D structure using only a 2D drawing. How would you show every side, every angle, clearly and accurately? That’s where mastering projections comes in. Projection of Solids is the extension topic of Projection of Planes.

Projection of Solids

PRISM
Pyramid
CYLINDER AND CONE

The solids may be in one of the following positions:

  • Axis perpendicular to the H.P.
  • Axis perpendicular to the V.P.
  • Axis parallel to both the H.P. and the V.P. (i.e., perpendicular to the profile plane)
  • Axis inclined to the H.P. and parallel to the V.P.
  • Axis inclined to the V.P. and parallel to the H.P.

Problems and Solution of Projection of solids

Problem – 1: A pentagonal prism of base side 30 mm and axis 70 mm has a corners on the H.P. and the axis is inclined at 45° to the H.P. Draw its projection when the plane containing the resting corner and the axis is parallel.

Problem: A square prism of base side 40 mm and axis 60 mm is resting on its base on the ground. Draw its projections when (a) a face is perpendicular to the V.P., (b) a face is inclined at 30° to the V.P., (c) all the faces are equally inclined to the V.P.

Problem: A hexagonal pyramid of base side 30 mm and axis 60 mm has an edge of its base on the ground. Its axis is inclined at 30° to the ground and parallel to the V.P. Draw its projections.

Problem: A cylinder of base diameter 50 mm and axis 70 mm has a generator in the V.P. and inclined at 45° to the H.P. Draw its projections.

Problem: A hexagonal prism of base edge 30 mm and axis 70 mm has an edge of its base in the V.P. such that the axis is inclined at 30° to the V.P. and parallel to the H.P. Draw its projections.

This drawing shows the orthographic and isometric projection of a hexagonal prism:

  • First Stage (Left Side):
    • Top view: Hexagon (30 mm side).
    • Front view: Rectangle with 70 mm height.
  • Second Stage (Right Side):
    • Final projections with rotated side view at 30° to the horizontal.
    • Helps visualize the true 3D shape of the prism.

Problem: A cone of base diameter 50 mm and axis 60 mm has a generator in the V.P. and the axis parallel to the H.P. Draw its projections.

The orthographic projection of a cone with a 50 mm base diameter and 60 mm height. It includes:

  • Top View: Circular base divided into 12 equal parts.
  • Front View: Triangular cone shape.

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