2. Lesson 4- Sketching and Dimensioning Techniques
Cave paintings discovered in France indicate that human beings have been using pictures to communicate ideas for tens of thousands of years. The expression “one picture is worth a thousand words” is used in many places. In engineering and architecture, a picture is used to express a design idea, concept, or potential solution for a problem. Sometimes the picture is a simple sketch; other times it is a complex drawing.

3. Lesson 4 Sketching and Dimensioning Techniques
Brainstorming sessions are used to generate a multitude of ideas to solve a problem. After the ideas are narrowed down to a few, a sketch pad is generally used to more clearly express the idea in order for all participants to have a visual understanding of the potential solution.

4. Lesson 4 Sketching and Dimensioning Techniques
In these lessons you will learn how to sketch using several different techniques, such as thumbnail and isometric sketching, methods widely used to communicate ideas. In addition they will learn the basics of dimensioning and annotating drawings. Students will practice creating one- and two-point perspective and orthographic views, sometimes referred to as multiple views, of an object.

5. Lesson 4- Concepts
The ability to create a rapid, accurate sketch is an important skill to communicate ideas.  
Orthographic drawings of an object are used to provide information that a perspective drawing may not be able to show.
Engineers apply dimensions to drawings to communicate size information.

6. Lesson 4- Performance Objectives
It is expected that students will:
Summarize the reasoning for using sketching as a communication tool.
Use visualization, spatial reasoning, and geometric shapes to sketch two and three dimensional shapes.
Recognize and create thumbnail, perspective, isometric, and orthographic sketches.
Communicate ideas for a design using various sketching methods, notes, and drafting views.
Dimension an orthographic sketch following the guidelines of dimensioning.

7. Activity 4.1- Sketching Techniques

8. Purposes of Sketching Think through a design Convey your ideas
Sketching Techniques
1.4.1– Sketching Techniques
Purposes of Sketching
Think through a design
Convey your ideas
Uses lines and symbols to describe a design
There are several purposes for creating sketches. Sketches help you to think through a design. They also help you convey your ideas to other people for better understanding. Sketching is a language just like any other. The difference is that in sketching we use lines and symbols to describe the shape, size, and even the function of a design.

9. Common Uses of Sketching
Sketching Techniques
1.4.1– Sketching Techniques
Common Uses of Sketching
Brainstorm
Communicate
Document Measurements
In the engineering field, sketches are often used to brainstorm ideas and to solve problems. Many times they are used to communicate ideas to other people for better understanding or explanation of an object. Sketches are also used to document measurements taken in the field to be used back at the office.

10. Advantages of Sketching
Sketching Techniques
1.4.1– Sketching Techniques
Advantages of Sketching
Convenient
Inexpensive
Creating and using sketches provides several advantages. Sketches are convenient and can be created almost anywhere, plus they are inexpensive. Few additional materials are needed. Only pencil and paper is required to create a sketch.

11. Sketch Type and Detail Simple & Less Detail Vs. Highly Detailed &
Complex
Speed, with neatness, is Key
When creating a quality sketch, three factors must be considered ** The first factor to consider is which type of sketch will serve your purpose the best – a simple and rough sketch or ** a more highly detailed and realistic sketch. **Another factor to consider when creating a sketch is speed. Quick sketches usually contain little detail and information.

12. Type of Sketch and Amount of Detail
Depends upon:
Purpose – What do you want the sketch to show?
Audience – Who is going to view the sketch?
Design Intent – Does the sketch show enough detail for full understanding of an idea?
When creating a sketch, the overall quality is determined by three main factors. The quality depends on the **purpose, **the audience, and **the intent of the design. You want the sketch to represent the design intent or show enough detail for full understanding of an idea.

13. Sketching Techniques
Sketching Techniques
1.4.1– Sketching Techniques
Use the following slides to properly sketch several different size;
Lines
Arcs
Circles
There are some skills that we need to discuss, such as vertical lines, horizontal lines, plus inclined or slanted lines. To create any of the lines shown, it is important to plot or locate two points, the start and end points, before you attempt to draw the line.
Inclined Line
Horizontal (Run)
Vertical(Rise)

14. Sketching Techniques Sketching a Line 1) Identify Start and End Points
When sketching a line, first, plot the start and end points. Next, draw short line segments between the two points so that you have an idea of where the line will be drawn. Finally, darken the smaller lines so that one solid line appears between the two points. You will repeat the same process when drawing vertical or inclined lines.
2) Sketch short light lines connecting points
3) Darken line with short overlapping strokes

15. Sketching Techniques Sketching an Arc Mark off equal Sketch diagonal
Draw light
intersecting lines
Mark off equal
distances where
arc will start
Sketch diagonal
line between marks
To sketch an arc or curved line, you will need to complete a five step process. ** In step one sketch a vertical and horizontal line so that they intersect each other. ** Next make a mark of equal distance from the intersection where the arc will be located. Do this on each of the intersecting lines. ** For step three, draw a line to connect the two marks.

16. Sketching Techniques Sketching an Arc Continued Sketch the arc
4) Find center mark
** In step four, draw an approximate mark where the center of the arc will be drawn. ** Finally draw a curved line by connecting the three points together to form the arc shape.
6) Darken object lines

17. Sketching Techniques Sketching a Circle 3) Sketch Find Center and
Set up the radius
3) Sketch
diagonals
2) Lightly square in
the diameter
To sketch a circle, you will complete a five step process. In step one, create a horizontal and vertical line the size of the desired diameter of the circle. Make sure the two lines intersect each other at the midpoints of the lines. For step two, sketch a square the size of the desired diameter. Make all horizontal and vertical lines the same length to ensure a true square shape. In step three, create diagonal or slanted lines connecting the four original diameter size marks together.

18. Sketching Techniques Sketching a Circle Continued 5) Sketch arcs
6) Darken object
4) Identify triangle
centers
Now in step four, create a mark at the center location for each of the triangles. In the last step, sketch curved lines using the original diameter marks and the center marks just created to complete a perfect circle.

19. Alphabet of Lines
Sketching Techniques
1.4.1– Sketching Techniques A
Construction Line- Thin light lines that serve as guides while sketching or drawing. B
Object Line- A heavy solid line used on a drawing to represent the outline of an object after drawing construction lines.
There are four main types of lines used when creating sketches. In the following slides, you will be shown each type of line and where it is used on a sketch. C
Hidden Line- A line type that represents an edge that is not directly visible because it is behind or beneath another surface. D
Center Line- A line type that is used to indicate the center of circles and arcs.
Also can be used to indicate the axis of symmetry.

20. 7. Label each of the line types in the drawing below.

21. Alphabet of Lines Construction Line
Sketching Techniques
1.4.1– Sketching Techniques
Alphabet of Lines
Construction Line
Thin light lines that serve as guides while sketching or drawing.
Construction lines are lightly drawn lines used as guides to help all other lines and shapes to be drawn properly. If you hold your paper an arm’s length away, you should not be able to see construction lines. They can even be erased after the object is sketched.

22. Alphabet of Lines Object Line
Sketching Techniques
1.4.1– Sketching Techniques
Alphabet of Lines
A heavy solid line used on a drawing to represent the outline of an object after drawing construction lines.
Object Line
Object lines are thick lines used to show visible edges of an object. In many situations, construction lines turn into object.

23. Alphabet of Lines Hidden Line
Sketching Techniques
1.4.1– Sketching Techniques
Alphabet of Lines
A line type that represents an edge that is not directly visible because it is behind or beneath another surface.
Hidden Line
Hidden lines are used to show interior details not visible from the outside of the object being drawn. In this part a hidden line is used to show a hole not visible from this side of the object.

24. Alphabet of Lines Center Line
Sketching Techniques
1.4.1– Sketching Techniques
Alphabet of Lines
A line type that is used to indicate the axis of symmetry for a part or feature. Required in circles and arcs.
Center Line
Center lines are used to define the center of the arcs, circles, or symmetrical parts. They are drawn half as thick as object lines. In this example the center line is used to define or show the center of the hole in the object.

25. Size and Proportion Size: Height, width, depth distances
Proportion: Size of an object relative to another object
Although you have learned to draw lines and arcs, ** you cannot communicate properly until you understand how to sketch with the correct size and proportion. ** Size is the height, width, and depth of the object you are sketching. You must consider the size of the object that you are sketching in order to properly communicate size. ** Proportion is the size of an object relative to other objects. For example, when you have two objects that are five feet apart in real life, the two objects must appear to be the same distance apart in your sketch.

26. Size and Proportion
Compare the houses. Which one is drawn to proportion?
As you see in the completed house on the left, the size of the windows is too large for the house. This means that the windows were not drawn proportionally to the size of the house. The windows should have been drawn proportionally to fit the house as they do in the house on the right.

27. Size and Proportion Technique
Using a pencil to measure for size
You can use a simple technique to create proper size and proportion when sketching. ** Use a pencil to help you measure size. Hold your pencil at arm’s length. Use the top of the pencil and your thumb as a distance for the height of the window. This distance will be used as a reference for sketching the side of the house on the next slide.

28. Size and Proportion Technique
Using a pencil to measure for size
As you can see in the completed house, the unit for the numbered dimensions is windows. This means that the size of one window was used to make the rest of the house relative in size or proportionally drawn. The use of graph paper also helps in creating proper size and proportion.

29. Shading Provides a more realistic image Shows how light
reflects on the object
More appropriate for an artistic sketch
** Shading allows us to create more realistic images by ** showing how light reflects on the object. We use shading in engineering graphics to help show depth and add realism. ** Shading is more appropriate for an artistic rendition rather than a technical sketch.

30. Conclusion Questions:
Answer the following questions in complete sentences using specific details.
1. How will sketching help you solve technical problems?
2. Why is it important to use the proper line types?

31. Sketching Techniques
1.4.1– Sketching Techniques
Image Resources
Microsoft, Inc. (2008). Clip Art. Retrieved October 20, 2008, from