1. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Project Lead The Way, Inc.
Copyright 2007

2. Line Conventions Line Conventions Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Project Lead The Way, Inc.
Copyright 2007

3. Line Conventions Line Weight – the thickness (darkness) of line
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Standardization of lines
Lines of varying styles and line weights are used in specific ways to develop and communicate graphic messages about an object’s geometry. The next few slides show some basic line conventions and their use.
Line Weight – the thickness (darkness) of line
Project Lead The Way, Inc.
Copyright 2007

4. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Construction Lines
Construction Line: Very lightly drawn lines used as guides to help draw all other lines and shapes properly.
Construction Lines
Project Lead The Way, Inc.
Copyright 2007

5. Line Conventions Object Lines: Lines are thick
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Object Line
Object Lines: Lines are thick
and dark; used to define the
object
Object Line
Object Line
Project Lead The Way, Inc.
Copyright 2007

6. Stop here Line Conventions Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Stop here
Project Lead The Way, Inc.
Copyright 2007

7. Line Conventions Hidden Lines
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Hidden Line: Lines used to show interior detail that is not visible from the current outside view of the part.
medium weight lines
Hidden Lines
Project Lead The Way, Inc.
Copyright 2007

8. Hidden Lines Line Conventions Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Hidden Lines
Project Lead The Way, Inc.
Copyright 2007

9. Stop Here Line Conventions Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Stop Here
Project Lead The Way, Inc.
Copyright 2007

10. Line Conventions Center Lines Center Mark
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Center Lines
Centerline and Center Marks: Lines that define
the center of arcs, circles, or
Symmetrical parts. They are half as thick as an object line.
Light weight lines
Center Mark
Project Lead The Way, Inc.
Copyright 2007

11. Center Lines Line Conventions Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Center Lines
Project Lead The Way, Inc.
Copyright 2007

12. Center lines Line Conventions Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Project Lead The Way, Inc.
Copyright 2007

13. Line Conventions
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Dimension Lines: Lines that are used to show distance.
Arrows are drawn on the ends to show where the dimension line starts and ends.
The actual distance is usually located in the middle of the line to let you know the distance being communicated.
Light weight lines
Dimension Line
Dimension Line
Project Lead The Way, Inc.
Copyright 2007

14. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Extension Lines: Lines used to show where a dimension starts and stops on an object.
Used with dimension lines to properly dimension an object.
The line is 1/16” away from the part as to not get confused with the object lines.
Light lines
Extension Line
Extension Line
Project Lead The Way, Inc.
Copyright 2007

15. Line Conventions
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Leader Lines: Line used to connect a feature of a drawing to some information about that feature.
The leader line might point to a feature that is a point, a line, a surface, a circle, arc, or even the whole part
On the other end of the leader line there will be information regarding the dimension, a note or an item number.
A leader line says, “Look here and read this!!!”
Don’t want to write the information in the drawing so use a leader line.
Light lines
Leader Line
Sand surface
Leader Line 4
Project Lead The Way, Inc.
Copyright 2007

16. Object Lines Construction Lines Light Leader Lines Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Object Lines
Very Light
Construction Lines
Light
Leader Lines
Project Lead The Way, Inc.
Copyright 2007

17. STOP HERE FOR THE CHAPTER
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
STOP HERE FOR THE CHAPTER
Project Lead The Way, Inc.
Copyright 2007

18. Line Conventions Section Lines: Lines are used
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Section Lines: Lines are used
to define where there is material after a part of the object is cut away.
Section Line
Section Line
Project Lead The Way, Inc.
Copyright 2007

19. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Short-Break Line
Short-Break Line: A freehand drawn line that shows where a part is
broken to reveal detail behind the part or to shorten a
long continuous part.
Project Lead The Way, Inc.
Copyright 2007

20. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Long-Break Line
Long-Break Lines: Used to shorten very long objects that do not change in detail.
The line is usually represented as a jagged cut or break.
Project Lead The Way, Inc.
Copyright 2007

21. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Cutting Plane Line: is the plane that cuts through a component to create a sectional view showing the internal details that cannot be seen from the outside
Cutting Plane Line
Project Lead The Way, Inc.
Copyright 2007

22. Object Lines
Construction Lines
Light
Leader Lines

23. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Line Conventions
Though these standards relate to technical drawing, which is far more precise than freehand sketching, their conventions should be used as a guide when sketching.
Project Lead The Way, Inc.
Copyright 2007

24. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Precedence of Lines
When sketching complex objects, different line types will often overlap each other. Therefore, line precedence must be exercised.
Project Lead The Way, Inc.
Copyright 2007

25. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Precedence of Lines
The following are rules that govern line precedence in sketches and technical drawings.
Object lines take precedence over hidden and center lines.
Hidden lines take precedence over center lines.
Cutting plane lines take precedence over all others.
Project Lead The Way, Inc.
Copyright 2007

26. Precedence of Lines Object lines take precedence over
Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Precedence of Lines
Object lines take precedence over
the hidden lines.
An object line here takes
precedence over the center line.
Project Lead The Way, Inc.
Copyright 2007

27. Line Conventions
Introduction to Engineering DesignTM
Unit 1 – Lesson 1.2 – Intro to Technical Sketching
Precedence of Lines
An object line here takes
precedence over the hidden line.
Object lines take precedence over the center lines you would see from the hole.
Object lines take precedence over the hidden lines you would see from the slot cut out in top view.
An object line here takes
precedence over the center line.
Project Lead The Way, Inc.
Copyright 2007