Chapter 5Sketching Applications

Why Sketching?• Sketching (i.e., freehand drawing)

– Drawing without drafting equipment– Only paper, pencil, and an eraser needed– Fast, visual communication– Asset for communicating technical concepts

• All lines are related in sketches– Size and direction

• Sketches should be proportional– Actual size depends on paper and sketch size

Sketching Tools & Materials• Soft lead pencil• Initially type of paper is not

critical as long as the idea can be conveyed

• Grid paper is best to define scale

Sketching Tools and Materials• Pencils

– Should have soft lead• Common No. 2• Mechanical pencil with H, F, or HB lead• Automatic 0.7-mm or 0.9-mm pencil with F or HB lead

– Point should be slightly rounded

• Paper– Almost any type works

Sketching Straight Lines

Sketching Circular Objects• Trammel Method

– Make a trammel or use scale– Place pencil on one point while holding the end

and rotate around center point– Nail and string method

• Hand compass Method– Use your hand as the center and rotate the paper

PracticeSketch freehand

How did you do?

Measurement and Proportion• Proportion of lines to each other are more important then the

size of the sketch itself• The first line sketched determines the ______of the drawing• The second line determines the ______ of the drawing• Use your pencil to establish measurements if no scale is

available

Sketching Procedures• Before sketching try to visualize the object or finished product• Sketch very light lines of the outline• Add details being careful to keep the proportion correct• Darken in the desired lines of the final sketch• Use a grid to create irregular shapes

Use Construction LinesBox out drawings

Multiview Projection• Establishes two or more views of an object

as projected on two or more planes – Uses orthographic projection techniques

• Elevations– Two-dimensional exterior views of a structure

• Proper view selection– Six primary views

Multiview Details• Use the front, left side, right side, and back

as elevationsWhere do all drawings come from?

Floor PlansRoof PlanCross SectionElectricalSite

• Mirror Line• Height• Width

________________ or _______________Sketches____________ = 90º

Practical Application of Orthographic Projection• Any projection of features onto an imaginary perpendicular plane

– Lines of sight are perpendicular to the plane– Objects are true size if they are parallel to the plane– Objects are foreshortened if they are not parallel to the plane– Alignment of views is critical

Application Exercise

One and Two Point ___________Projection Sketches

• Determine best view for the front

• Set up isometric axes• Sketch overall block• Add details

Setting up Sketches• Perspective

– Vanishing point(s)– Horizon Line– Ground Line

• Isometric– Horizontal ground line– Perpendicular line– Two 30° lines