sketching prof. jon southen october 8, 2008. sketches from leonardo da vinci’s design notebook
TRANSCRIPT
Sketching
Prof. Jon Southen
October 8, 2008
Sketches from Leonardo da Vinci’s Design Notebook
Thomas Edison's Sketches
First sketch of the phonograph, 1877
A sketch showing the basic circuit for energizing a discharge tube.
Sketching in Engineering
Text Reference:Bertoline-Wiebe, Fundamentals of Graphics
Communication, Fifth EditionThis lecture: Chapter 2
Sketching in Engineering
Objectives Demonstrate the Importance of Sketching.
Sketching in Engineering
Objectives Demonstrate the Importance of Sketching. Introduce Sketching Techniques
Drawing simple lines and curves, using construction lines, bounding lines, etc.
The Importance of Sketching
Sketching quickly communicates design ideas. It’s a necessary skill for any technical person. Often part of the creative process – Generation
of Design Concepts. Helps to visualize 3D objects from 2D images. Used extensively in Engineering.
The Importance of SketchingNot Just for Design - Engineering Inspections
The Importance of Sketching
In your field book......to describe what you saw (e.g. damage/defects)
The Importance of Sketching
Sketching quickly communicates design ideas. It’s a necessary skill for any technical person. Often part of the creative process – Generation
of Design Concepts. Helps to visualize 3D objects from 2D images. Used extensively in Engineering.
The Role of Sketching
Talking sketches Informal communication
Thinking sketchesTo help you think creatively
Prescriptive sketchesDocument design ideas
Problem Definition:
Sketch shows cross-section of a Hong Kong skyscraper tested in the wind tunnel.
Tuned mass damper required to prevent excessive vibrations.
Example in Design
Preliminary Idea Generation:
After considering other alternatives, a pendulum damper was selected as the best option.
The design progressed with this basic shape.
Example in Design
Constraints:
After some detailed engineering calculations, the final requirements were determined and details could be worked out with sketches.
The final unit has to meet all of the constraints.
Example in Design
Example in Design
Final detailed CAD model of the prototype
Basis of tender documents
Example in Design
Working Drawings
Working Drawings – cont’d
The Importance of Sketching
Plan good for Layout and Cost.
But how will it look?
The Importance of Sketching Evaluate Options/Different Concepts Helps to visualize in 3-D.
The Importance of Sketching
To help sort out the details.
What do you need…
Sketching tools - pencils, paper and a big eraser.
patience and practice – with these you can be good at making quick, clear, well-proportioned sketches regardless of your experience or natural ability
Sketching Practice Techniques Contour Sketching
Negative-space Sketching
Upside-down Sketching
Contour Sketching
Contour Sketching
Negative-Space Sketching
Fundamental Techniques
Straight Lines
Curved Lines
Construction Lines and Proportions
Lettering
Mechanical
Sketched
Good
No!
No!
No!
Straight Lines
MARK END-POINTSMARK END-POINTS
Begin using grid paper, or the clear side of graph paper.
Mark the endpoints of the line to be drawn
Lines should be straight, continuous and dark with uniform thickness
Straight Lines
Long lines are difficult. Use grid paper as a guide or reduce the size of the sketch.
Do not fix paper to the table, and rotate it to find an easier angle for drawing lines.
Draw away from yourself or at a slight angle.
Relax your hand (Go for it!).
Straight Lines
Line Types
Line Precedence
Visible lines have top priority
Hidden lines do not cross or have priority over visible lines
Centre lines do not cross or have priority over visible or hidden lines
Curved Lines Curved lines are essentially
interpolations between 2 or more points. These points are typically marked as intersecting lines or tangents
Circles and ellipses require construction lines.
Control the degree of curvature - not too flat, not too curved
Construction Lines
The first step is drawing construction lines that form the backbone the sketch.
These very light thin lines roughly layout some of the details
Do not erase them!
Curved Lines
Circles and Ellipses
Circles and Ellipses
Use diagonals to proportion
Creating a Proportioned Sketch
Lettering
Creativity Vignette
Design Sketch of a Concept
Requirements: Each individual should prepare freehand sketches of one design alternative, using proper sketching practices. Do not use a straightedge to draw your sketch. Your sketches should clearly communicate the design concept and must include sufficient views, sections and details. Use text annotations to describe and explain parts of the sketch. Ask your team mates for feedback. Are they able to understand what you have drawn? Better even, ask other teams to evaluate your sketches or have a TA look at them.
Evaluation Criteria: The evaluation criteria specify criteria and assessment descriptors in the following four broad categories. Points will be awarded in each category as shown below.
Assessment category Maximum points
Sketch Quality: Sketch fits the page well Lines are clear and well drawn Appropriate line thicknesses used Appropriate use of annotation
1.0 1.0 1.0 1.0
Multi-views: Views properly placed and aligned
and necessary sections and details provided
Each view is correctly drawn and important lines shown
Proper use of hidden lines, center lines etc.
1.5 1.5
1.0
Dimensioning: Dimensions drawn correctly Circules and curves dimensioned Properly
1.0 1.0
Total 10
Due week of October 27
Sketching in Engineering
Review Look over practice problems from textbook to improve
your sketching technique
Next Class Types of Engineering Drawings Projections Views