1. EF101 Analysis & Skills Module 1
EF101 Analysis & Skills Module 1.3 Engineering Graphics Terminology and Conventions

2. Reading Review Why are multi-view orthographic projections used?
What is a disadvantage of multi-view orthographic projections?
Which type of multi-view projection is used in the United States?
Name the components that are typically part of a set of working drawings?

3. Reading Review What are construction lines?
What are two types of pictorial sketches commonly used in freehand sketching?
Which type of 3D projection places the principal face of an object parallel to the plane of the paper?
What type of projection results in multiple views?

4. Design Process / Working Drawings

5. Sketch Types

6. Glass Box

7. Unfolding Glass Box

8. View Relationships

9. Projection Types Controls the placement of views
Depicted on drawings by the truncated cone symbol
Third Angle
United States and Great Britain
Top view - above front view.
Right side - right of front view
Same as “Glass box” unfolding
First Angle
Rest of world
Top view - below front view.
Right side - left of front view
We will only use third-angle projections in EF101

10. What can a Line Represent?

11. Orthographic Projection Surface Types
Parallel – appear true size in one view, and as an edge (line) in other views
Inclined – appear distorted in two views, and as an edge in the view perpendicular to the surface
Oblique – appear distorted in all three views

12. Hidden Lines Dashed lines, lighter (thinner) than object lines.
Used in orthographic projection views to represent edges that are “hidden” from the line of sight for a view.
Not used in isometric or oblique views.

13. Hidden Lines Example

14. Centerlines
Locate the center of circles and the axis of cylindrical features.

15. Line Types and Precedence
Object lines dark and thick
Hidden lines dark, dashed and thin
Centerlines dark, “long–short–long”, thin
Construction lines very thin and light

16. Coordinate System Placement
Placement of a coordinate system is arbitrary, but once placed you must be consistent in its use.
AutoCAD’s convention is that the XY plane of the coordinate system represents the view it calls the top view.
We place a coordinate system on sketches to help us to get used to working with a consistent coordinate system.

17. Multi-view sketching Determine necessary views
Plan layout, spacing, scale to fit paper
Develop drawing: block in views, make sure width, height, depth are correct in all views
Add features in each view.
Check work

18. Sketch as an Orthographic Projection

19. Isometric sketching Use paper in landscape mode Determine orientation
Determine scale and location to fit object in the center of the page
Sketch the bounding box
Work from faces and corners
Parallel lines are parallel.
“Connect the dots” i.e. connect known locations.

20. Sketch as an Isometric Projection