Engineering Drawing

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Engineering Drawing
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What is engineering drawing
An engineering drawing, a type of technical
drawing, which is used to fully and clearly
define requirements for engineered items with
scales.
Engineering drawing example
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Types of Drawings
All Drawings
Artistic
Technical
Sketches (conceptual)
Diagrams (design technical)
Drawings (technical/engineering)
simulated perspective
Multi view orthographic
Diagram (design plan)
Diagram (technical)
Isometric projection
Oblique projection
Less technical
More technical
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Conceptual Sketches

• When any idea comes in your mind, you draw a
  simple or rough drawing of the object without
  using any drawing instruments or tolls and this
  is called a conceptual sketch.

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Importance of Engineering Drawings

• Helps as a reference to workers, technicians or
  architects.
• Easy to understand Since a picture is easiest
  method than thousand words, a technical drawing
  is a much more effective tool for engineers than
  a written plan.
• Engineering drawings is used in all engineering
  fields, including, but not limited to, civil
  engineering, electrical engineering, mechanical
  engineering and architecture.

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Sketch Vs Engineering drawing

• Sketch made without drafting tools... Just
  pencil and paper. Scale is approximate, not
  accurate, but the sketch should still look like
  the object.
• Engineering Drawing Made with drafting tools...
  Ruler, set squares, protractor and compass.
  Scale should be accurate and the drawing
  carefully made.

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Projection

• If straight lines are drawn from various points
  on the contour (A contour line is a imaginary
  line which connects points of equal elevation) of
  an object to meet a plane, the object is said to
  be projected on that plane.
• The figure formed by joining, in correct
  sequence, the points at which these lines meet
  the plane, is called the projection of the
  object.
• The lines from the object to the plane are called
  projectors.

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Projection
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Projection Types

• Orthographic projection
• Isometric projection

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Orthographic projection

• Orthographic Projection is a way of drawing an
  3D object from different directions.
• Usually a front, side and plan view are drawn so
  that a person looking at the drawing can see all
  the important sides.
• Orthographic drawings are useful especially when
  a design has been developed to a stage whereby it
  is almost ready to manufacture.

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Orthographic projection views
OBJECT
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Orthographic projection

• As shown in the earlier slide, if an observer at
  position A  moves to infinity, the projectors
  to his eyes becomes parallel to the object and he
  observes the same shape and size as that of the
  object. The view so formed is known as the
  orthographic projection.
• Similarly, the parallel projectors shall form
  the pictures on the respective picture planes
  from the positions B and C.

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Isometric Projection

• Isometric projection is a method for visually
  representing three-dimensional objects in two
  dimensions in technical and engineering drawings
• Isometric drawings consist of two-dimensional
  drawings that are tilted at some angle to expose
  other views and give the viewer the illusion that
  what he or she is viewing is a three-dimensional
  drawing.

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An Isometric Drawing
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Comparison of Projections
Orthographic Isometric
Used for Drafting, maps, floor plans Technical drawings, drafting, conceptual sketches (sometimes) Used for Conceptual sketches, technical drawings (sometimes)
Orthographic is a set of 3 Plane Projections Isometric is a 3-D sketch
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Diagrams

• Diagrams are simplified versions of a drawing.
  Diagrams show how an object works, not
  necessarily how it looks.
• Diagrams often use symbols rather than actual
  pictures to represent things.

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A Circuit Diagram

• Doesnt show what the circuit looks like, but
  tells an electrician how its all connected.