Engineering Drawing Conventions: Orthographic, Isometric and Section Views
The main types of engineering drawing and their conventions: orthographic projection for exact sizes, isometric drawing for a 3D view, section views for internal detail, and the line types, dimensions and scale that go with them.
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Drawing a design
Engineers use drawings to share exactly what a product should look like and how big it is. Different drawings do different jobs: some give precise sizes, some show the product in 3D, and some cut through to reveal the inside. This module looks at the main drawing types and the conventions that make them clear to read.
Drawing vocabulary
Learn these four terms before you study the drawing types.
Orthographic vs isometric
The two most common drawings do very different jobs.
Right drawing for the job
A top answer picks the drawing type by its purpose: an orthographic projection when exact sizes are needed to make a part, an isometric drawing to show what it looks like, and a section view to reveal what is inside. Remember that a dashed line means a hidden edge you cannot see from the surface.
Match the drawing
- orthographic projection
- isometric drawing
- section view
- assembly drawing
- gives the exact sizes for making a part
- shows what the product looks like in 3D
- reveals the hidden inside of a part
- shows how the parts fit together
Match the line
- a solid line
- a dashed line
- a centre line
- a dimension
- a visible edge of the object
- a hidden edge behind the surface
- the middle of a round feature
- a measured size on the drawing
Which drawing for sizes?
An engineer needs the exact sizes of a bracket, seen from the front, side and top, so it can be made. Which drawing type is best?
- An orthographic projection.
- An isometric drawing.
- A section view.
- A rough freehand sketch.
Spot the flat views
Select the TWO views that are part of an orthographic projection.
- The front view.
- The side view.
- A 3D isometric view.
- A cut-through section view.
Set out a drawing
Put the steps of setting out an engineering drawing in order, earliest first.
- Choose the right drawing type
- Decide the scale to use
- Draw the views with the correct lines
- Add the dimensions and a title block
Complete the facts
A single 3D picture drawn on angled lines is an _____ drawing. A cut-through view that reveals the inside is a _____ view. A hidden edge is shown with a _____ line. A visible edge is shown with a _____ line. A measured size on a drawing is a _____.
Work out the real size
A drawing is made at a scale of 1 to 2, so every 1 millimetre on the drawing is 2 millimetres in real life. A line measures 30 millimetres on the drawing. Multiply 30 by 2 to find the real length. What is it in millimetres?
Find the orthographic views
Tap the TWO views that belong to an orthographic projection.
- front view
- side view
- isometric view
- section view
Which drawing type?
Read what each engineer needs and choose the best drawing type.
- An engineer needs the exact width and height of a part so it can be machined
- A catalogue needs a realistic 3D picture of the finished product
- A drawing must show the hollow inside of a pipe fitting
Explain the drawings
Explain the three main types of engineering drawing and when a designer would use each one.
- Describe an orthographic projection and its use
- Describe an isometric drawing and its use
- Explain when a section view is useful