Publisher The Goodheart-Willcox Co., Inc. Tinley Park, Illinois

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PowerPoint Presentation
PublisherThe Goodheart-Willcox Co., Inc.Tinley
Park, Illinois
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Chapter 4

• Drawing Instruments and Techniques

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Orthographic Projection

• Orthographic projection is the most basic
  drafting technique.
• A means of representing the height, width, and
  depth of a three-dimensional object on
  two-dimensional paper.
• The object is viewed at infinity, thus projection
  lines are parallel to each other.
• Typically, three views are used.

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Orthographic Projection

• This camp cottage shows the arrangement of views
  in orthographic projection.

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Three Principal Views

• The three principal views in orthographic
  projection are the top, front, and right side
  views.
• In architectural drafting, the views are similar
  but have different names.
• The top view of a house is called a plan view
  used as the basis for most other drawings.

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Three Principal Views

• The floor plan is a top view in section taken
  about half way up the wall.
• The front elevation in architectural drafting is
  the same as the front view in mechanical
  drafting.
• Architectural drafters ordinarily draw a view of
  each side of the structure, which are called
  elevations.

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Three Principal Views

• How orthographic views are projected.

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Architectural Alphabet of Lines

• Border Lines
• Object Lines
• Hidden Lines
• Centerlines
• Extension Lines
• Dimension Lines

• Long Break Lines
• Short Break Lines
• Cutting-Plane Lines
• Section Lines
• Guidelines
• Construction Lines

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Border Lines

• Border lines are very heavy lines used to form a
  boundary for the drawing.
• Use a 0.70mm pen.

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Object Lines

• Object lines are heavy lines that outline
  features of an object.
• Use a 0.50mm pen.

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Hidden Lines

• Hidden lines represent edges that are behind a
  visible surface in a given view.
• Use a 0.35mm pen.

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Centerlines

• Centerlines indicate the center of holes and
  symmetrical objects, such as windows and doors.
• Use a 0.25mm pen.

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Extension Lines
Extension lines

• Extension lines are used to denote the
  termination points of a dimension line.
• Use a 0.25mm pen.

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Dimension Lines

• Dimension lines are used to show size and
  location. They have a dimension figure halfway
  between the ends of the dimension line.
• Use a 0.25mm pen.

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Long Break Lines

• Long break lines are used to show that not all of
  the part is shown.
• Use a 0.25mm pen.

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Short Break Lines

• Short break lines show part of the object broken
  away.
• Use a 0.70mm pen.

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Cutting-Plane Lines

• Cutting-plane lines are used to show where the
  object is sectioned.
• Use a 0.70mm pen.

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Section (Crosshatch) Lines

• Section lines or crosshatch lines are used to
  show that a feature is sectioned.
• May represent different types of material.
• Use a 0.25mm pen.

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Guidelines

• Guidelines are used in hand lettering to keep
  lettering straight.
• Very light lines.
• Drawn in pencil only.

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Construction Lines

• Construction lines are used in the process of
  constructing a drawing.
• Should not be reproduced.
• Not inked or plotted.

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Line Type Application

• In manual drafting, all lines are black and vary
  only in width. Colors may be used in CADD.

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Architectural Lettering

• There is no single style of architectural
  lettering. Most lean toward the artistic.
• Develop your own style.

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Developing a Lettering Style

• Words should not appear to run together or be too
  far apart.
• Space between words should usually equal the
  height of an uppercase letter.
• Most information lettered on a drawing is 1/8" or
  3/32" high.
• Try making the first letter in each word 1/8" and
  the remainder 3/32" high.

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