SKETCHING and LETTERING Print multiple handouts on one

SKETCHING and LETTERING Print multiple handouts on one page to save paper Select File – Print Edit the following selections to read: Select the OK button 12/12/2021 1

Example Freehand Sketch for Concept Development

Supplies • Required – HB lead in a 0. 7 mm pencil (medium grade) – Eraser – 8. 5” x 11” Engineering Paper (Green) • Five blocks per inch • Recommended – 6 H wooden pencil for light lines, i. e. , construction lines 12/12/2021 3

Why is Sketching Important? • Fast way to get from mental image to hard copy so ideas can be shared. • Most designs start with numerous sketches as part of the iterative process. • May be situations where its crucial to be able to produce neat accurate sketches (I. e. meetings, business dinners) no computer available! 12/12/2021 4

Objectives of Sketching • Freehand sketches are used to communicate with others, so they should be neat and correctly prepared. – Legibility • must be able to read and interpret – Accuracy • valid and convey proper size or shape – Neatness • no smudges, rips, etc. . . • Fast – time is money • Economical 12/12/2021 5

Exercise • On the back of this packet, sketch the following: – – – Horizontal line Vertical line Angled line Circle Sketch several more lines making some darker than others. • Looking at the lines you just sketched, answer the following questions: – – – 12/12/2021 How How How horizontal is the horizontal line? vertical is the vertical line? straight is the angled line? round is the circle? did you do creating some lines darker than others? 6

Good Sketching Techniques • Communicate subject clearly. • Sketches should be proportional (scale not as important). • Use different line weights (thicknesses) to show the relative importance of different lines. – Correct grade of lead helps to create good quality sketches. – Object lines should be thick and black, so they stand out from the dimensions, notes, and other lines. • However, it is best to sketch lightly to get proper size and proportions before darkening the lines. (Having trouble, try a 6 H wooden pencil. ) – Use two different diameter pencils (0. 7 mm vs. 0. 3 mm) – Lean pencil to achieve different line thickness – Use short overlapping strokes 12/12/2021 7

Sketching Lines • Great descriptions and examples on page 57 (MGC) – Practical Tips Drawing freehand lines 12/12/2021 8

Problems? • Check out – Practical Tips Freehand lines, page 56. – Figure 3. 7 Technique of Lines, page 59 – Figure 3. 8 Contrast of Lines, page 59 12/12/2021 9

Exercise • On a piece of engineering graph paper, using short overlapping strokes sketch the following: – – Horizontal line Vertical line Angled line Sketch several more lines making some darker than others. • Looking at the lines you just sketched, answer the following questions: – – How How horizontal is the horizontal line? vertical is the vertical line? straight is the angled line? did you do creating some lines darker than others? • Which method did you have more control over – solid line or a line consisting of short overlapping strokes? 12/12/2021 10

Sketching Circles and Arcs • Circles – MGC: Step by Step 3. 1, page 60 – Use Method A, B or C • Use light pencil strokes for construction and darken when you are satisfied with appearance – Instructor must be able to see LIGHT construction lines • Arcs – MGC: Step by Step 3. 3, page 62 – Carefully locate tangencies – Sketch curves first and then add straight lines tangent to them. This is easier than trying to make a curve tangent to straight lines. 12/12/2021 11

Sketching Lines Tangent to an Arc • Locate the center of a lightly sketched circle or arc. • Lightly sketch in the lines to which the arc is tangent. • Lightly sketch a line perpendicular to each line through the center of the arc or circle. • Lightly sketch circle through tangent points • Darken arc and lines. 12/12/2021 12

Exercise • On a piece of engineering graph paper, using short overlapping strokes sketch several circles and arcs. • Looking at the circles and arcs you just sketched, how round are the circles and arcs? • Which method did you have more control over – solid or a circle/arc consisting of short overlapping strokes? • Connect several circles with lines and locate the tangent points. • Darken appropriately. 12/12/2021 13

Alphabet of Lines • Line patterns communicate what the line represents in the drawing • Line patterns tell you information such as whether the line is hidden, visible, or a centerline (Figure 3. 6 page 58 MGC) 12/12/2021 14

Alphabet of Lines Thick Thin Thick Thin Thick 12/12/2021 Thin 15

Appropriate Line Weights 12/12/2021 Incorrect Correct 16

Contrast of Lines Figure 3. 8 Contrast of Lines 12/12/2021 17

Technique of Lines Figure 3. 7 Technique of Lines 12/12/2021 18

Scale • Sketches are not usually made to a particular scale. • It is important to keep the sketch in proportion • Use grid paper or estimate proportions by comparison 12/12/2021 19

Sketch Large Features, Then Add Small Details • Look at overall dimensions and lightly block in. • Block in secondary details lightly. • Add final details • Darken sketch. 12/12/2021 20

Develop Sketch by Blocking In 1. 2. 3. 4. 12/12/2021 21

Enlarging Proportions • Lay a grid over existing picture • Draw larger grid • Look at each portion of the object. How does it enter and exit each grid box. • Sketch in lightly in enlarged boxes 12/12/2021 22

Sketch the Figure Below Hands-On 3. 1, page 64, GMC 12/12/2021 23

Additional Practice • Worksheet 3. 3 at back of text. 12/12/2021 24

Sketching Summary • Almost all engineering designs start with simple sketches! • Quality is one of the most important aspects of sketching. • Sketched lines should be bold freehand lines. Do NOT use a straight edge. • The subject of the sketch should stand out clearly. • Using the correct lead grades and good techniques for sketching will help your sketches look their best. 12/12/2021 25

Lettering • Neat legible lettering is used to add dimensions and notes to sketches. • Poor lettering can ruin an otherwise good sketch. • Engineering lettering is usually drawn with HB or other relatively soft lead. • Use 1/8” uppercase Gothic single-stroke letters