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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 (3D) 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