Lesson Notes By Weeks and Term v4 - SHS 3
Design and Drawing for Manufacture
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Design and Drawing for Manufacture
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Manufacturing Engineering
Class: SHS 3
Term: 1st Term
Week: 20
Grade code: 2.2.1.LI.2
Strand code: 2
Sub-strand code: 1
Content standard code: 2.2.1.CS.2
Indicator code: 2.2.1.LI.2
Theme: Design and Prototyping
Subtheme: Design and Drawing for Manufacture
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
This lesson introduces a fundamental concept in engineering and design: First Angle Orthographic Projection. Imagine you are a skilled carpenter in Accra who has a brilliant new design for a school desk. How do you share this design with a welder in Kumasi who needs to build the metal frame, or a factory in Tema that needs to mass-produce 1,000 of them? You cannot just describe it over the phone. You need a universal language of drawing that everyone understands, ensuring every desk is made exactly the same. First Angle Orthographic Projection is that language.
A. What is Orthographic Projection?
The word "orthographic" comes from two Greek words: 'orthos' (meaning straight or right-angled) and 'graphos' (meaning drawing).
So, Orthographic Projection is a way of drawing a 3D object from different directions using parallel lines that are perpendicular (at 90°) to the drawing plane.
Think of it this way: Imagine you are holding a small box. To get the Front View, you look at it straight-on from the front. You only see its height and width. To get the Top View, you float directly above it and look straight down. You only see its width and depth. To get the Side View, you move to the side and look at it straight-on. You only see its height and depth.