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True Length

  1. Sep 20, 2009 #1
    In my engineering class we are learning about finding the true length of a line. I don't understand it at all. We basically work with 2D views of a line in either the profile, front, or horizontal view. I don't understand how to get from one view to the next. Does anyone know of any good internet resources to help me understand this concept? I tried googling it but I couldn't really find anything too good.
     
  2. jcsd
  3. Sep 21, 2009 #2
    Imagine a toothpick frozen in an ice cube. Look at it from the top, the front, and the left side. How do you determine the toothpick's length? Picture the the toothpick being the diagonal (hypotenuse) of a right triangle resting on the bottom of the cube. The length of the base of the triangle (B) is the same length you see in the top view. The height of the triangle (H) is the height you see in any side view. The length of the triangle's hypotenuse (the toothpick length) is the square root of A squared + B squared, which is the familiar Pythagorean formula.
     
  4. Sep 22, 2009 #3

    FredGarvin

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    Last edited by a moderator: Apr 24, 2017
  5. Sep 23, 2009 #4
    are each three of the views on different planes that are perpendicular to each other, for example: top, front, side?

    if they are then find lengths of the lines in each view. say L1,L2, and L3
    to find the true length the formula is: sqrt[(L1^2)+(L2^2)+(L3^2)]
    this is the 3D formulation of the pythagorean theorem.
    if 1 or more of the view planes are not perpendicular to the other two and the line is not parallel to at least 1 plane then you'd need to find the angle at which the planes intersect each other and through a more tedious calculation you find the true length.

    what program are you using?
     
  6. Sep 23, 2009 #5

    FredGarvin

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    If they're learning the way they should, the program is called a pencil-paper-tsquare v1.0.
     
  7. Sep 23, 2009 #6
    lol, i actually googled that.
    i only asked because i dont know how profile, horizontal, and front relate to each other.
     
  8. Sep 24, 2009 #7

    FredGarvin

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    Did anything come up? Google is awesome.
     
  9. Sep 24, 2009 #8
    well what do you think came up? this page is the first on the list!
     
  10. Sep 27, 2009 #9
    Try this:
    http://www2.bakersfieldcollege.edu/mrozell/documents/Engr%20B24/Ch16_1.pdf [Broken]

    full course at:
    http://www2.bakersfieldcollege.edu/mrozell/ [Broken]
     
    Last edited by a moderator: May 4, 2017
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