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Learn the importance of sketching in engineering design and how to make simple sketches of basic shapes. Explore 3D coordinate systems, draw isometric and oblique sketches, and develop advanced sketching skills for complex objects.
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Chapter 2 Sketching
Objectives Explain the importance of sketching in the engineering design process. Make simple sketches of basic shapes such as lines, circles, and ellipses.
Objectives Use 3-D coordinate systems, particularly right-handed systems. Draw simple isometric sketches from coded plans.
Objectives Make simple oblique pictorial sketches. Use advanced sketching skills for complex objects.
Sketching in the Engineering Design Process A sketch is any drawing made without the use of drawing instruments
Sketching in the Engineering Design Process • "Engineer-to-engineer" graphic assist in a verbal explanation • Compromise between time and clarity • Used where a lot of control exists • Etcheverry Hall Model Shop
Sketching in theEngineering Design Process Quickly prepared Simply constructed Used to improve spatial reasoning ability
Sketching Lines Light, brisk strokes to establish lines Let inertia of the arm assist, don't over emphasize finger control Eyes away from paper, use peripheral vision
Sketching Lines Use destination points for sighting Rotate the paper to assist line sketching
Sketching Lines • Start by creating light short • lines in one pass • Next make a second pass • to darken the lines
Sketching Curved Entities Establish boundary lines Establish crossing points Establish tangent points and angles Use light stokes, then fill in
Objects • 3-D is best way to communicate • Make the foundation: • The view to best represent • Space it occupies
Objects • Add the frame: • The object outline • Finish the product: • Small details, texture • Amount depends on purpose
Construction Lines Light lines used as a guide to create an object Used to outline the shape of the object that is being sketched Can be used to locate the center of holes
Coordinate Systems • 3-D coordinate system • Represents space by three mutually perpendicular coordinate axes • Typically the x-, y-, and z-axes
Isometric Paper • Used to help create isometric sketches • Isometric dots paper • Oriented such that the lines are already drawn at 120°
Oblique Pictorials Another type of sketch you can create to show a 3-D object Usually preferred for freehand sketching because of a specialized grid
Oblique Pictorials Three dimensions of the object are shown with the height and width of the object in the plane of the paper. The third dimension (depth) is receding off at an angle from the others.
Circular Holes in Oblique Pictorial Sketches When circular holes appear in an oblique pictorial sketch, as with isometric sketches, you show the partial edges of the back circle where they are visible through the hole.
Shading and Other Special Effects Shading can be used to improve the quality of your pictorial sketches. Another common use of shading is to show curvature of a surface.
