1.2 Orthographic Projection

• Meaning of orthographic projection and its importance in engineering
• Representation of a three-dimensional object by two-dimensional views
• Planes of projection: the vertical plane and the horizontal plane
• The four quadrants of a plane and the quadrant method
• The principal views: plan, front elevation and end elevation
• First angle projection and the relative position of the views
• Third angle projection and the relative position of the views
• The projection symbol for first and third angle
• Line types and conventions used in orthographic drawings
• Sectional views and cutting planes
• Standard dimensioning: extension lines, dimension lines, arrowheads, figures, units and symbols
• Applications of orthographic projection in electrical technology

• explain the concept of orthographic projection in representation of three-dimensional objects
• apply quadrant method in locating planes of objects in orthographic projection
• interpret the relative position of views in first and third angle projections
• apply proper dimensioning techniques to orthographic drawings
• recognise the importance of orthographic projection in representing electrical components and layouts

“Why are orthographic drawings important in the engineering field?”

“How are orthographic projection views dimensioned?”

The titles are open to everyone. Reading a lesson needs an account — sign in or create one.

1. What orthographic projection is
   40 min · 1 practice tasks · quiz
   Introduce orthographic projection and explain why engineers use it.
2. Describing a three-dimensional object
   40 min · 1 practice tasks · quiz
   Describe a solid by its faces, edges and vertices.
3. The planes of projection
   40 min · 1 practice tasks · quiz
   Explain the vertical plane and the horizontal plane.
4. The four quadrants of a plane
   40 min · 1 practice tasks · quiz
   Apply the quadrant method to locate the planes of an object.
5. The principal views
   40 min · 1 practice tasks · quiz
   Identify the plan, front elevation and end elevation and how they are arranged.
6. First angle projection
   40 min · 1 practice tasks · quiz
   Explain the arrangement of views in first angle projection.
7. Third angle projection
   40 min · 1 practice tasks · quiz
   Explain the arrangement of views in third angle projection.
8. Comparing first and third angle
   40 min · 1 practice tasks · quiz
   Compare the relative position of views in first and third angle projections.
9. The projection symbol
   40 min · 1 practice tasks · quiz
   Identify the symbol that shows which projection a drawing uses.
10. Line types and conventions
    40 min · 1 practice tasks · quiz
    Use the standard line types of an orthographic drawing.
11. Sectional views
    40 min · 1 practice tasks · quiz
    Use a sectional view to show the inside of an object.
12. Extension and dimension lines
    40 min · 1 practice tasks · quiz
    Place extension lines and dimension lines correctly.
13. Figures, units and symbols
    40 min · 1 practice tasks · quiz
    Add figures, units and symbols to dimensions.
14. Rules for good dimensioning
    40 min · 1 practice tasks · quiz
    Apply the rules that keep a drawing clear and correct.
15. Drawing electrical components
    40 min · 1 practice tasks · quiz
    Draw and dimension an electrical component in orthographic projection.
16. Applications in electrical technology
    40 min · 1 practice tasks · quiz
    Discuss how orthographic drawings are used in electrical work.
17. Reading orthographic drawings
    40 min · 1 practice tasks · quiz
    Interpret flat views and build up the solid they describe.
18. The importance of orthographic drawings
    40 min · 1 practice tasks · quiz
    Review the sub strand and explain why orthographic drawings matter.