What is the difference between orthographic and isometric projection?

Orthographic projection shows an object as separate flat 2D views (front, plan and side), each drawn true to size, and is used for working drawings because each view can be dimensioned for manufacture. Isometric projection shows the object as a single 3D pictorial view, with vertical lines vertical and the horizontal directions at 30 degrees, and is used to show what the finished object looks like to a client or in a catalogue.

What is the difference between CAD and CAM?

CAD (computer-aided design) is using software to create, edit and store the design as a 2D drawing or 3D model. CAM (computer-aided manufacture) is using a computer to control the machines that make the part. The CAD model is converted into a CAM program, which a CNC machine follows to cut the part automatically. So CAD designs the part and CAM makes it.

What are the advantages and disadvantages of CAD/CAM?

Advantages include fast editing, exact and consistent dimensions, easy sharing and storage, on-screen testing and simulation so fewer prototypes are needed, direct links from CAD to CAM and CNC, and high accuracy and repeatability in manufacture. Disadvantages include the high cost of software, hardware and CNC machines, the need for skilled staff to design and program, job losses as automation replaces manual machinists, and reliance on the computer system.

What are the new and emerging technologies in this course?

The main ones are robotics and automation (programmable machines for repetitive or hazardous tasks such as welding and assembly), additive manufacturing or 3D printing (building a part layer by layer from a CAD model, ideal for complex shapes and one-off prototypes), and new materials and components (stronger lightweight composites, smart materials and smaller cheaper electronics). Each brings benefits but also issues such as cost and job losses.

Northern IrelandEngineering & Manufacturing

Engineering Drawing, CAD and CAM: study guide - CCEA GCSE

A study guide to engineering drawing, CAD and CAM in CCEA GCSE Engineering and Manufacturing: orthographic and isometric drawing, computer-aided design, computer-aided manufacture and CNC, and new and emerging technologies.

Generated by Claude Opus 4.88 min readCCEA Units 1 and 3Updated 2026-06-14

Reviewed by: AI editorial process; not yet individually human-reviewed

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What this topic covers
How it is examined
Key distinctions to learn
How to revise it

Engineers must communicate a design clearly and then make it. CCEA tests engineering drawing conventions, the role of CAD and CAM, and the new technologies changing manufacture. Expect "explain the difference" and balanced advantage/disadvantage questions.

What this topic covers

Engineering drawing conventions - third-angle orthographic and isometric projection, sectioning, dimensioning and standard line types.
Computer-aided design (CAD) - what it is and its advantages and disadvantages.
CAM and CNC - how a CAD model drives automated manufacture, with pros and cons.
New and emerging technologies - robotics and automation, additive manufacturing (3D printing), and new materials and components.

How it is examined

Expect questions comparing orthographic and isometric drawing, identifying line types, explaining the CAD-to-CAM-to-CNC chain, and giving balanced advantages and disadvantages of CAD, CNC and robots. Many questions ask you to weigh benefits against impacts such as cost and job losses.

Key distinctions to learn

Orthographic = flat 2D views for manufacture; isometric = one 3D picture at 30 degrees for showing.
CAD designs the part; CAM controls the machines that make it; CNC is the automated machine that runs the CAM program.
3D printing adds material layer by layer; CNC machining removes material as waste.

How to revise it

Learn the line types and views. Be able to label visible, hidden and centre lines and name the orthographic views.
Master the CAD-CAM-CNC chain. Say clearly which step designs, which programs and which makes.
Prepare balanced lists. For CAD, CNC and robots, learn two advantages and two disadvantages each.
Contrast 3D printing and CNC. Adding versus removing material, and when each is the better choice.
Use CCEA past papers to see how drawing and technology questions are phrased.

Work through the linked dot points for full worked answers and exam-style questions on each part of the topic.

Sources & how we know this

CCEA GCSE Engineering and Manufacturing specification (2017) — CCEA (2017)
CCEA GCSE Engineering and Manufacturing: Unit 3.3.6 new and emerging technologies fact files — CCEA (2024)