Orthographic Projection and Modelling

Drawings a workshop can build from

A neat sketch shows an idea, but a workshop needs a precise working drawing it can measure and make from. That is what an orthographic projection gives: the object shown in separate flat views, drawn to scale with dimensions. This module works through orthographic views, the first-angle and third-angle layouts, scaling, and why designers build models before the real thing.

Drawing words to know

Learn these before you set out the views.

First angle against third angle

Both show the same views; they differ in where each view is placed.

Place by the rule, keep the scale

In the exam, first say which projection you are using, then place the views by its rule. Third angle keeps each view on the same side you look from, so looking down puts the plan up top and looking from the end puts that view out to the side. First angle flips every view across to the far side instead. When a drawing is scaled, change every real length by the same ratio, and keep that scale identical on each view.

Match the term

Match the view

Where does the top view go?

In third-angle projection, where is the top view placed?

• Above the front view
• Below the front view
• Far to the left, on its own
• Inside the front view

True about working drawings

Select the TWO true statements about orthographic working drawings.

• An orthographic projection shows an object in separate flat views
• In third angle the top view sits above the front view
• First and third angle place the views in the same positions
• A model is only ever made after the product is manufactured

Scale it down

A shelf is 600 mm long in real life and is drawn at a scale of 1 to 3. Divide the real length by 3 to find the length on the drawing in mm. What is the answer?

Order the drawing steps

Put the steps of laying out a working drawing in order, earliest first.

• Choose the projection and a suitable scale
• Draw the front view first
• Place the top view above and the side view beside it
• Add the dimensions

Complete the rules

An _____ projection shows an object as separate flat views. In _____ angle projection the top view sits above the front view. Making a rough version of a design to test it is called _____. When a drawing is scaled down, every real length is made _____ by the same factor.

Spot the third-angle facts

Tap the TWO statements that are true of third-angle projection.

• the top view is placed above the front view
• every view is drawn to the same scale
• the top view is placed below the front view
• each view is drawn to a different scale

Choose the right tool

Read each task and choose the best answer.

• You need a precise drawing that a workshop can measure and make the part from. Which do you use?
• A drawing shows the top view sitting above the front view. Which projection is it?
• Before making the final product, you build a quick card version to check its size and shape. What is this?

Explain working drawings

Explain what an orthographic projection is, how third-angle projection arranges the views, and why designers make models.

• Say what an orthographic projection shows
• Explain where the front, top and side views go in third angle
• Explain why a designer makes a model before manufacture