1. Sketching Techniques and Practice!
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Sketching Techniques and Practice!

2. Purposes of Sketching Think through a design Convey your ideas
Sketching Techniques
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning 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.

3. Common Uses of Sketching
Sketching Techniques
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning 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.

4. Advantages of Sketching
Sketching Techniques
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning 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.

5. Pictorial Sketches Show shape of object Show height, width, and depth
Sketching Practice
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Pictorial Sketches
Show shape of object
Show height, width, and depth
Common types:
Isometric
Perspective
Pictorial drawings show the shape of an object viewed by the human eye. Pictorial sketches are sketches that show height, width, and depth all in one view. Common types of pictorial drawings are isometric and perspective.

6. Sketching Practice
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Isometric Sketch
Width and depth lines are drawn at 30° from the horizon line.
One view shows height, width, and depth.

7. Orthographic (Multiview Drawings)
Sketching Practice
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Orthographic (Multiview Drawings)
Pictorial sketches help engineers explain ideas and communicate to the customer what the final part will look like. Unfortunately, pictorial drawings have some disadvantages. Foreshortened views and distorted features do not allow for accurate prototyping. In order for parts to be accurately depicted, you typically need views that directly portray each surface. The arrows represent the line of sight associated with each view. Any object possesses six views. Notice the similarities between the front and back, the right and left, the top and bottom views.

8. Orthographic (Multiview) Sketching
Sketching Practice
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Orthographic (Multiview) Sketching
An orthographic sketch is used to show true size and shape.
Each view is adjacent to the other as if unfolded from a 3D shape.
Notice the top view is directly above the front with the right side view directly to the right of the front.
In order to obtain these straight line views, we have a type of drawing called orthographic projection, also known as multiview drawing. Orthographic projection is a way to project a view based on a line of sight that is perpendicular to that view.

9. Orthographic – View Selection
Sketching Practice
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Orthographic – View Selection
Characteristics for selecting the front view
Best shape & details
Longest dimensions
Fewest hidden lines
Most natural position
Finding the best view of a part can be difficult. Two or more sides may seem to be the best choice for the front view. Consider these four main details when selecting the front view. First, which side shows the best shape or details of the object? Which side shows the longest dimensions of the object? Which side shows the fewest hidden lines? Which side shows the most natural position of how the object will be used?
Which view do you think should be the front?

10. Sketching Techniques Sketching a Circle 1) Set up the diameter
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Sketching Techniques
Sketching a Circle
1) Set up the
diameter
2) Square in the
diameter
3) Sketch
diagonals
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.

11. Sketching Techniques Sketching a Circle 4) Identify triangle centers
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Sketching Techniques
Sketching a Circle
4) Identify triangle
centers
5) Sketch arcs
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.

12. Alphabet of Lines Construction Object Hidden Center
Sketching Techniques
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Alphabet of Lines
Construction
Object
Hidden
Center
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.

13. Alphabet of Lines Construction Line Construction Line
Sketching Techniques
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Alphabet of Lines
Construction Line
Construction Line
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.

14. Alphabet of Lines Object Line Sketching Techniques
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Alphabet of Lines
Object Line
Object lines are thick lines used to show visible edges of an object. In many situations, construction lines turn into object.

15. Alphabet of Lines Hidden Line Sketching Techniques
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Alphabet of Lines
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.

16. Alphabet of Lines Center Line Sketching Techniques
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Alphabet of Lines
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.

17. Precedence of Lines Object lines exist over hidden and center lines.
Sketching Practice
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Precedence of Lines
Example 1
Object line over
hidden lines
Object lines exist over hidden and center lines.
Hidden lines exist over center lines.
Example 2
Object line
over center line
In multiple view drawings, different line types often compete for space; therefore, we have line precedence.
Object lines exist over hidden and center lines. In example 1, the object lines take precedence over the hidden lines that you would see from the hole. In example 2, an object line takes precedence over the center line. However, we draw short thin lines beyond the object to show that a center line exists underneath the object line.
Hidden lines exist over center lines. (no example of this shown)

18. Thumbnail Isometric Sketch
Sketching Practice
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Thumbnail Isometric Sketch
Copy and label this cube on your isometric axis.

19. 3D Sketching Techniques
Sketching Practice
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
3D Sketching Techniques
Isometric Grid Paper
A technique you can use when making an isometric sketch is to use isometric grid paper. This helps with determining the right angle for your sketch. You can also create a more professional look to your sketch by turning the paper over and drawing the sketch on the white side of the sheet but still utilizing the grid. Your finished product will look cleaner if it is on the white side of the paper.

20. Sketching Techniques
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Image Resources
Microsoft, Inc. (2008). Clip Art. Retrieved October 20, 2008, from