1. Sketching Resource Presentation

2. Sketching Techniques Sketching Techniques PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Sketching Techniques
Design and Modeling
© 2011 Project Lead The Way, Inc.

3. Common Uses of Sketching
Sketching Techniques
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Common Uses of Sketching
Brainstorm
Communicate
Document
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 for documentation.

4. Advantages of Hand Sketching
Sketching Techniques
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Advantages of Hand Sketching
Convenient
Inexpensive
Creating and using hand 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 (or a napkin) is required to create a sketch. In many cases, you may be brainstorming and simply documenting your ideas. In other cases, you may be trying to communicate technical information. In this presentation we will be talking about techniques commonly used in technical sketching.

5. Sketching Techniques Lines Inclined Line Vertical Line Horizontal Line
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Sketching Techniques
Lines
Inclined Line
Run
Rise
Vertical Line
Horizontal Line
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.

6. Sketching Techniques Sketching a Line 1) 2) 3) Sketching Techniques
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Sketching Techniques
Sketching a Line 1) 2)
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. 3)

7. Sketching Techniques Sketching a Circle 1) Set up the diameter
PLTW Gateway®
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.

8. Sketching Techniques Sketching a Circle 4) Identify triangle centers
PLTW Gateway®
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.

9. Alphabet of Lines Construction Object Hidden Center
Sketching Techniques
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Alphabet of Lines
Construction
Object
Hidden
There are four basic types of lines used when creating sketches. In the following slides, you will be shown each type of line and how it is used on a sketch.
Construction lines are lightly drawn lines that you can use to help you draw other lines 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.
Object lines are thick lines used to show visible edges of an object. In many situations, construction lines are converted to object lines.
Hidden lines are used to show interior details not visible from the a particular view of the object.
Center lines are used to define the center of the arcs, circles, or symmetrical parts. They are drawn half as thick as object lines.
Center

10. Alphabet of Lines Sketching Techniques PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Alphabet of Lines
Consider this object in the following sketches that illustrate different types of lines.

11. Front View Object Line Center Line Center Line Sketching Techniques
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Front View
Object Line
Center Line
Center Line
This view represents the part as seen from the front of the object. The line of sight is indicated by the red arrow.
Which line is an object line?
[Click to reveal an answer.]
Which line is a center line?

12. Top View Object Line Hidden Line Center Line Sketching Techniques
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Top View
Object Line
Hidden Line
Center Line
This view represents the part as seen from the top of the object. The line of sight is indicated by the red arrow.
Which line is an object line?
[Click to reveal an answer.]
Which line is a hidden line?
[Click to reveal an answer.] In this view hidden lines is used to show the edges of a hole not visible from the top of the object.
Which line is a center line?
[Click to reveal an answer.] In this view the center line is used to identify the center of the hole in the object.

13. Right View Hidden Line Center Line Object Line Sketching Techniques
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Right View
Hidden Line
Center Line
Object Line
This view represents the part as seen from the right side of the object. The line of sight is indicated by the red arrow.
Which line is an object line?
[Click to reveal an answer.]
Which line is a hidden line?
[Click to reveal an answer.] In this view hidden lines are used to indicate the edges of the through hole as well as the bottom of the slot that can not be seen when viewing the part from the right side.
Which line is a center line?

14. Isometric View Object Line Construction Line Sketching Techniques
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Isometric View
Object Line
Construction Line
Which line is an object line?
[Click to reveal an answer.]
Which line is a construction line?

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

16. “One picture is worth a thousand words.”
Sketching Practice
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Sketching Practice
“One picture is worth a thousand words.”
Design and Modeling
© 2011 Project Lead The Way, Inc.

17. Pictorial Sketches Show shape of object Show height, width, and depth
Sketching Practice
PLTW Gateway®
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.

18. Sketching Practice
PLTW Gateway®
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.

19. 3D Sketching Techniques
Sketching Practice
PLTW Gateway®
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. Thumbnail Isometric Sketch
Sketching Practice
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Thumbnail Isometric Sketch
Copy and label this cube on your isometric axis.

21. Isometric Thumbnail Sketch
Sketching Practice
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Isometric Thumbnail Sketch
Additive and Subtractive 3D sketch
Follow the steps in your activity to complete this drawing on the isometric graph paper.
An isometric sketch shows an object in which the width and depth are projected at 30 degree angles from the horizontal axis. The height, width, and depth values are all at the same scale.

22. Sketching Practice
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Perspective
Perspective is a way to draw that shows a view of the object in the most realistic way.
Vanishing points are used to guide the lines in the object to the horizon line or the horizontal line you see at your line of sight.

23. One-Point Perspective
Sketching Practice
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
One-Point Perspective
Vanishing Point (VP)
All lines in the depth project to one point (the vanishing point).
The location of the vanishing point is based on your line of sight.
Copy this one-point perspective sketch onto your activity. Label the front, top, and right side.
This is an example of one point perspective. Notice that all lines in the depth project to one point, the vanishing point. The location of the vanishing point is based on your line of sight.

24. Two-Point Perspective
Sketching Practice
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Two-Point Perspective
VP1
VP2
In two-point perspective, the width lines converge on one vanishing point (VP1), and the depth lines converge on the other vanishing point (VP2).
Copy this two-point perspective onto your activity sheet. Label the top, front, and side.

25. Orthographic (Multiview Drawings)
Sketching Practice
PLTW Gateway®
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.

26. Orthographic (Multiview) Sketching
Sketching Practice
PLTW Gateway®
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.

27. Orthographic (Multiview) Sketching
Sketching Practice
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Orthographic (Multiview) Sketching
Copy this orthographic sketch onto your activity sheet. Label the top, front, and right side.
Don’t forget the hidden lines.
Note the orientation of the views. Each view is adjacent to the other as if they were unfolded from a 3D shape. Front, top, and right side views are used most often.

28. Orthographic – View Selection
Sketching Practice
PLTW Gateway®
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?

29. Precedence of Lines Object lines exist over hidden and center lines.
Sketching Practice
PLTW Gateway®
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)

30. Dimensioning Dimensioning PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimensioning
Design and Modeling
© 2011 Project Lead The Way, Inc.

31. Dimensioning
Why Dimension?
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Engineers, designers, and engineering technologists need to know
Size
and
Location of all features
Size dimensions describe the size of each geometric feature.
With respect to linear dimensions, size dimensions are sometimes referred to as overall dimensions and will tell the viewer the overall width, height, and depth of an object.
Location dimensions show the location of each geometric feature within an object or view.
Location dimensions tell the viewer where edges occur inside an object view.

32. Dimension Completely Width Dimensioning PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimension Completely
Width
The students should notice the location of the dimensions and how the largest are on the top or outside and they become gradually smaller as you get closer to the object.

33. Dimension Completely Width Height Dimensioning PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimension Completely
Width
Height
Talk to the students about over-dimensioning and what is meant by over-dimensioning.

34. Dimension Completely Width Height Depth Dimensioning PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimension Completely
Width
Height
Depth
Point out the location dimensions for the circle.
Center mark and centerline bisectors are needed to show where the center of a circle is.

35. Dimension Line Types Dimension Line Extension Line Leader Line
Dimensioning
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimension Line Types
Dimension Line
Extension Line
Dimension Line - Thin lines capped with arrowheads which may be broken along their length to provide space for the dimension numerals. Whenever possible try to center the dimension between the arrows.
Extension Line - Thin lines used to establish the extent of a dimension. Extension lines should not touch the object. Notice the space between the object line and the extension line, and between the center line and the extension line in the hole location dimension. Extension lines can be shared between individual dimension lines.
Leader Line - Lines that are thin and used to connect a specific note to a feature.
Point out the symbol for diameter.
Leader Line

36. ¼ in. scale or 4 squares = 1 in.
Dimensioning
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Your Turn to Practice
¼ in. scale or 4 squares = 1 in.
Give students time to complete this in Activity Dimensioning before going on to the next slide.
Tell students that it is not good dimensioning practice to dimension to a hidden line.
A future presentation will describe the guidelines associated with dimensioning.

37. Check Your Answers Dimensioning PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Check Your Answers
Orthographic graph paper is removed to better show dimensions.

38. Where are the Missing Dimensions?
Dimensioning
PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Where are the Missing Dimensions?
¼ in. scale or 4 squares = 1 in.
Give students time to complete this in Activity Dimensioning before going on to the next slide.

39. Here They Are Dimensioning PLTW Gateway®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Here They Are
Notice that the dimension value is all the same, but the dimension is measuring the size of different features. This is NOT duplicating a dimension. Often you will have the same value, but you will dimension different features.

40. What is Orthographic Projection?
Orthographic Projection is a method of representing a three dimensional object on paper using several two dimensional views.
It is the international language of Engineers and Designers
Created by Steven Colgan

41. How does it work?
We look directly at the different faces of the object (90˚ to the face) and draw the lines that we see.

42. How many views? One view is never enough to describe an object.
We need at least two views to accurately describe even the most simple of objects.
Generally we se three views and arrange them as shown in the movie
You can use as many views as the object requires.

44. Is it really an international language?
Yes. However America and Australia arrange the views differently.
This arrangement of views is called third angle projection.

46. How do I know which method is being used?
Each method has its own symbol and they are as follows
First angle projection
Third angle projection

47. How do I draw this symbol?
The recommended proportions for the symbol are as follows

48. Is that it?
Sometimes features of an object are hidden (for example they are at the back of the object)
To show these features we add dashed lines in their place.

50. Review Engineering Sketches
PLTW Gateway
Unit 2 – Lesson 2.3 – Automated Systems
Review Engineering Sketches
Automation and Robotics VEX
© 2011 Project Lead The Way, Inc.

51. Drawing styles Orthographic Projection Isometric Projection
Engineering Sketches
PLTW Gateway®
Unit 2 – Lesson 2.3 – Automated Systems
Drawing styles
Orthographic Projection
Shows one plane or surface at a time
Isometric Projection
Gives the illusion of depth

52. Orthographic Drawings
Engineering Sketches
PLTW Gateway®
Unit 2 – Lesson 2.3 – Automated Systems
Orthographic Drawings
Front view and top view included
Views are aligned
Top view is directly above and in line with front view

53. Orthographic Projection
Engineering Sketches
PLTW Gateway®
Unit 2 – Lesson 2.3 – Automated Systems
Orthographic Projection
Top View
Front View
In Design and Modeling™ unit students were taught that an Orthographic drawing has 3 views. In the interest of time and space on the lab sheets students will be required to sketch an orthographic drawing with only 2 views, but they should be the 2 views that demonstrate the most detail.

54. Isometric Drawings Pictorial drawings
Engineering Sketches
PLTW Gateway®
Unit 2 – Lesson 2.3 – Automated Systems
Isometric Drawings
Pictorial drawings
Three surfaces or planes shown together
30° angles are used to create drawings

55. Isometric Projection 30° Engineering Sketches PLTW Gateway®
Unit 2 – Lesson 2.3 – Automated Systems
Isometric Projection
30°