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COPY
Orthographic Projection NOTES

• (Copy into your notes section of your binder)

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Representational drawing and sketching

• Is concerned with "drawing what you see," or
  "drawing that which you imagine as if you
  actually saw it."
• (Sketch of garden shed)

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Technical drawing

• Is concerned with representing objects according
  to drawings that allow for
• Size, proportions, and structure - as well as
  appearance - to be shown.
• The most basic concept involved is the geometry
  of "projection."

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• An orthographic projection drawing - since it is
  a "flattened single view" of a (3-D) 3
  dimensional object - is an "exactly sized"
  representation of the real object on a 2
  dimensional surface (paper) AS SEEN IN THAT VIEW.

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Name these views (6)
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This process is called orthographic ("true
drawing") projection.
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It also works in reverse Dont copy

• a) If you correctly draw the individual views
• b) Fold them all up into a box with 90 degree
  corners
• c) Then project the corners of each drawing into
  the middle of the box the intersections of those
  lines will define the 3 dimensional object.

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Scaled Drawings

• It isnt usually practical to make the drawing
  actual size - most objects are larger than most
  pieces of paper.
• But if we use a standard unit of measure, and
  then reduce the size of the drawing by a standard
  ratio, we can specify the exact proportions and
  measurements of an object on a drawing that is
  much smaller than the real thing.

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• On a technical drawing using the metric measure,
  scaled in a proportion of 110,
• 1 mm will be equal to 10 mm actual size.
• On a technical drawing using the imperial
  measure, scaled in a proportion of 124,
• ½ inch will be equal to 12 inches actual size or
  1 inch is equal to 24 1nches.