Engineering H191 - Drafting / CAD
Design Process
Isometric Drawings
Lecture 6
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 1
Engineering H191 - Drafting / CAD
Topics For Today
• Using the Engineering Design Process
• More Freehand Sketching
– Isometric Sketches
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 2
Engineering H191 - Drafting / CAD
Engineering Design Process
•
1.
2.
3.
4.
•
AS SHOWN IN TOOLS AND TACTICS FOR DESIGN
DEFINING THE PROBLEM
FORMULATING SOLUTIONS
DEVELOPING MODELS AND PROTOTYPES
PRESENTING AND IMPLEMENTING THE DESIGN
You will do 1 & 2 in Homework this week
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 3
Engineering H191 - Drafting / CAD
Design
• What is design?
– PROCESS OF CONCEIVING OR INVENTING
IDEAS – Start w/ brainstorming for this lab
• The Art of Design
– DESIGN FOR FUNCTION AND PURPOSE
• The Practice of Engineering Design
– PRODUCT DESIGN
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 4
Engineering H191 - Drafting / CAD
Isometric Sketching
– Example & Ellipses
Goals
• A process for creating isometric drawings
• A process for sketching ellipses for isometric
drawings
Reference
• Earle, Section 13.7 & 13.8 and Chapter 25
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 5
Engineering H191 - Drafting / CAD
Making an Isometric Sketch
- Defining The Axis
60o
60o
30o
30o
Isometric Axis
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 6
Engineering H191 - Drafting / CAD
Making an Isometric Sketch
- Axis Convention
Height
Width
Depth
Isometric Axis Convention
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 7
Engineering H191 - Drafting / CAD
Object for Practice
How would you
sketch this object?
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 8
Engineering H191 - Drafting / CAD
Blocking in the Object
– Begin with Front Face
Front Face
Height
Start with
Isometric Axis
Width
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 9
Engineering H191 - Drafting / CAD
Blocking in the Object
– Add Side Face
Side Face
Height
Depth
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 10
Engineering H191 - Drafting / CAD
Top Face
Autumn Quarter
Blocking in the Object
– Add Top Face
Gateway Engineering Education Coalition
Lect 5
P. 11
Engineering H191 - Drafting / CAD
Adding Detail – Cut Outs
– Part 1
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 12
Engineering H191 - Drafting / CAD
Adding Detail – Cut Outs
– Part 2
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 13
Engineering H191 - Drafting / CAD
Adding Detail – Cut Outs
– Part 3
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 14
Engineering H191 - Drafting / CAD
Darken Final Lines
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 15
Engineering H191 - Drafting / CAD
Isometric ellipses
• In an isometric drawing, the object is viewed at an
angle, which makes circles appear as ellipses.
• Holes
• Cylinders
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 16
Engineering H191 - Drafting / CAD
Ellipses can be in any plane
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 17
Engineering H191 - Drafting / CAD
Sketching an Isometric of a Hollow Pipe
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 18
Engineering H191 - Drafting / CAD
Step 1 - Creating the Base Box
Diameter
Diameter
Autumn Quarter
Length
Gateway Engineering Education Coalition
Lect 5
P. 19
Engineering H191 - Drafting / CAD
Step 2 – Ellipse on Front Face
- corner to corner to get center
- lines to tangent points
Tangent Points
Lines to Tangent
Points
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 20
Engineering H191 - Drafting / CAD
Step 3 – Ellipse on Front Face
Sketch in Arcs
Tangent Points
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 21
Engineering H191 - Drafting / CAD
Step 4 – Finish Ellipse on Back Face, Profile
Repeat for ellipse on rear face
Draw Tangent Lines for Profile
Complete Visible Part of Back
Ellipse
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 22
Engineering H191 - Drafting / CAD
Step 5 – Ellipse for Hole on Front Face
Create Box for Hole
Sketch Ellipse
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 23
Engineering H191 - Drafting / CAD
Isometric of Hollow Pipe
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 24
Engineering H191 - Drafting / CAD
Defining Hidden and Center Lines
• Hidden Line – used to represent features that
cannot be seen in the current view
• Centerlines – used to represent symmetry and to
mark the center of circles and the axes of
cylinders, and the axes of symmetrical parts,
such as cylinders and bolts
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 25
Engineering H191 - Drafting / CAD
Example
Center Line
Hidden Line
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Gateway Engineering Education Coalition
Visible Line
Lect 5
P. 26
Engineering H191 - Drafting / CAD
Precedence of Lines
VISIBLE LINE takes precedence
over all other lines
HIDDEN LINE and CUTTING PLANE
LINE take precedence over center
lines
CENTER LINE does not have
precedence
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 27
Engineering H191 - Drafting / CAD
Example Application of Precedence
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 28
Engineering H191 - Drafting / CAD
Engineering Drawings
•
•
Drawing
Borderline and Title Block
– Borderline – Space outside left blank so details
are not lost if the edge of the drawing is torn
– Title Block – Information about who did the
drawing, when it was done, where it was saved
Autumn Quarter
Gateway Engineering Education Coalition
Lect 5
P. 29