This document outlines the steps and techniques for sketching various mechanical components and assemblies in a CAD software. It covers sketching a W16x50 beam, triangular plate, M20x2.5 threaded bolt, spur gears, and microgripper. For each example, it provides the dimensions, problem description, and specific sketching techniques and constraints used. The overall document serves as a tutorial for learning fundamental sketching and modeling skills in CAD.

1. Chapter 2 Sketching
1
Chapter 2
Sketching
2.1
Step-by-Step: W16x50 Beam
2.2
Step-by-Step: Triangular Plate
2.3
More Details
2.4
More Exercise: M20x2.5 Threaded Bolt
2.5
More Exercise: Spur Gears
2.6
More Exercise: Microgripper
2.7
Review

2. Chapter 2 Sketching
Section 2.1 W16x50 Beam
2
Section 2.1
W16x50 Beam
16.25"
.628"
.380"
7.07"
R.375"
W16x50
[1] Wide-flange
I-shape section.
[2] Nominal
depth 16 in.
[3] Weight 50
lb/ft.
Problem Description

3. Chapter 2 Sketching
Section 2.1 W16x50 Beam
3
• Start up <DesignModeler>
• Sketching/Modeling modes
• Draw>Rectangle
• Draw>Polyline
• Dimensions>General
• Dimension>Horizontal
• Dimensions>Display
• Dimensions>Move
• Modify>Copy/Paste
• Modify>Trim
• Modify>Fillet
• Constraints>Symmetry
• Auto Constraints
• Constraint Status
• Extrude
Techniques/Concepts

4. Chapter 2 Sketching
Section 2.1 W16x50 Beam
4
[1] Click: single
selection
[2] Control-click: add/
remove selection
[3] Click-sweep:
continuous selection.
[4] Right-click: open
context menu.
[5] Right-click-drag:
box zoom.
[6] Scroll-wheel: zoom
in/out.
[7] Middle-click-drag:
rotation.
Basic Mouse Operations

5. Chapter 2 Sketching
Section 2.2 Triangular Plate
5
Section 2.2
Triangular Plate
40mm
30 mm
300 mm
[1] The plate
has three
planes of
symmetry.
[2] Radii of
the fillets
are 10 mm.
Problem Description

6. Chapter 2 Sketching
Section 2.2 Triangular Plate
6
Techniques/Concepts
• Draw>Arc by Center
• Dimensions> Radius
• Modify>Replicate
• Modify>Offset
• Constraints>Equal Length
• Weak/Strong Dimensions
• Weak/Strong Constraints
• Selection Filter
• Single/Box Selection

7. Chapter 2 Sketching
Section 2.2 Triangular Plate
7
2D Graphics Controls
[8] <Undo>.
[9] <Redo>.
[2] <Zoom to Fit>.
[4] <Box Zoom>.[5] <Zoom>.
[1] <Look At Face/
Plane/Sketch>.
[6] <PreviousView>.
[7] <NextView>.[3] <Pan>.

8. Chapter 2 Sketching
Section 2.3 More Details
8
• Pull-down Menus
and Toolbars
• Mode Tabs
• Tree Outline
• Sketching
Toolboxes
• Graphics area
• DetailsView
• Status Bar
• Separators
Section 2.3 More Details

9. Chapter 2 Sketching
Section 2.3 More Details
9
[1] Currently
active plane.
[2] To create a
new plane,
click <New
Plane>.
[3] There are many ways
of creating new planes.
Sketching Planes
• A sketch must be created on a
sketching plane; each plane may
contain multiple sketches.
• In the very beginning of a
<DesignModeler> session, three
planes are automatically created:
<XYPlane>, <YZPlane>, and
<ZXPlane>.

10. Chapter 2 Sketching
Section 2.3 More Details
10
Sketches
• A sketch consists of points and edges; edges may be straight lines or curves.
• Multiple sketches may be created on a plane.
[1] To create a new sketch on
the active sketching plane,
click <New Sketch>.
[2] Currently
active sketch.

11. Chapter 2 Sketching
Section 2.3 More Details
11
Auto Constraints
• C
- The cursor is coincident with a line.
• P
- The cursor is coincident with another point.
• T
- The cursor is a tangent point.
• ⊥
- The cursor is a perpendicular foot.
• H
- The line is horizontal.
• V
- The line is vertical.
• //
- The line is parallel to another line.
• R
- The radius is equal to another radius.
[1]You can turn
on/off <Auto
Constraints>.

12. Chapter 2 Sketching
Section 2.3 More Details
12
Sketching Toolboxes

13. Chapter 2 Sketching
Section 2.4 M20x2.5 Threaded Bolt
13
Section 2.4
M20x2.5 Threaded Bolt
Problem Description
M20x2.5
[1] Metric
system.
[2] Nominal
diameter
d = 20 mm.
[3] Pitch
p = 2.5 mm.

14. Chapter 2 Sketching
Section 2.4 M20x2.5 Threaded Bolt
14
32
11×p=27.5
d1
d
External
threads
(bolt)
Internal
threads
(nut)
H
H
4
H
8
p
Minor diameter of internal thread d1
Nominal diameter d
H = ( 3 2)p = 2.165 mm
d1
= d − (5 8)H × 2 =17.294 mm
p

15. Chapter 2 Sketching
Section 2.4 M20x2.5 Threaded Bolt
15
• Dimensions>Angle
• Modify>Replicate
• Revolve
Techniques/Concepts

16. Chapter 2 Sketching
Section 2.5 Spur Gears
16
Section 2.5
Spur Gears
Problem Description
• To satisfy the fundamental law
of gearing, the gear profiles
are cut to an involute curve.

17. Chapter 2 Sketching
Section 2.5 Spur Gears
17
[7] Common
tangent of the
pitch circles.
[6] Contact
point (pitch
point).
[8] Line of action (common
normal of contacting gears).
The pressure angle is 20o
.
[3] Pitch circle
rp = 2.5 in.
[9] Addendum
ra = 2.75 in.
[10]
Dedendum
rd = 2.2 in.
[1] The driving
gear rotates
clockwise.
[2] The driven
gear rotates
counter-
clockwise.
[4] Pitch
circle of the
driving gear.
[5] Line of
centers.
[12] The fillet
has a radius of
0.1 in.
[11] The shaft has
a radius of 1.25 in.

18. Chapter 2 Sketching
Section 2.5 Spur Gears
18
Techniques/Concepts
• Draw>Construction Point
• Draw>Spline
• Modify>Replicate
• Constraints>Perpendicular

19. Chapter 2 Sketching
Section 2.6 Microgripper
19
Section 2.6
Microgripper
Problem Description
[2] Actuation
direction.
[1] Gripping
direction.
[3] SMA
actuator.
[4] Glass
bead.

20. Chapter 2 Sketching
Section 2.6 Microgripper
20
480
144
176
280
400140212
7747
87
20
R25R45
32
92
D30
Unit: µm
Thickness: 300 µm

21. Chapter 2 Sketching
Section 2.6 Microgripper
21
Techniques/Concepts
• Constraints>Equal Radius
• Copy bodies (Mirror)
• Create new sketch
• Constraints>Tangent
• Multiple parts