Chapter 5 Sketching Applications Introduction Sketching i e

Chapter 5 Sketching Applications

Introduction • Sketching (i. e. , freehand drawing) – Drawing without drafting equipment – Only paper, pencil, and an eraser needed – Fast, visual communication – Asset for communicating technical concepts

Introduction • Sketching may be used by: – Drafters – Computer-aided drafters – Architects – Designers

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 Lines • Techniques: – Trammel method – Hand-compass method – Nail-and-string method

Measurement Lines and Proportions • All lines are related in sketches – Size and direction • Sketches should be proportional – Actual size depends on paper and sketch size • Pencils – May used as a ruler for measurement

Measurement Lines and Proportions (cont’d. ) • Blocking – Helps determine shapes and proportions

Introduction to Multiview Sketches • Multiview projection – Views of an object as projected upon two or more picture planes in orthographic projection • Elevation views – Two-dimensional views established by a line of sight perpendicular to the object surface

Isometric Sketches • Provide a three-dimensional (3 D) pictorial representation of an object – Isometric lines are on or parallel to one of the three original isometric axes – Circles and arcs appear as ellipses

Orthographic Projection • Projection of features of an object onto an imaginary plane (i. e. , plane of projection) – Projection of features is made by lines of sight perpendicular to the plane of projection

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

Projection of Features from an Inclined Plane • In multiview projection, features of objects that are: – Parallel to projection planes appear true size and shape – Not parallel to projection planes are foreshortened, and not in true size and shape