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 Edition  This 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 Sketching Not 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 sketches  To help you think creatively Prescriptive sketches  Document 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

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

Negative- Space Sketching

Fundamental Techniques Straight Lines Curved Lines Construction Lines and Proportions Lettering

Mechanical Sketched Good No! Straight Lines MARK 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

Use diagonals to proportion

Creating a Proportioned Sketch

Lettering

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