Perimeter of a Cylinder

Discussion in 'SolidWorks' started by waligora, Dec 9, 2004.

  1. waligora

    waligora Guest

    I was told that an Enhancement Request was needed for this occurance,
    so I submitted one. Be aware of this.

    If you select the face of a rectangular plate, then use the Measure
    Tool a set of values will be shown. One of the values is Perimeter.
    As expected the value is the sum of the outer edges of the selected
    surface. This is well defined in all Geometry Texts that I know of.

    Now if you select the outer curved face of a cylinder (not the end) and
    use the Measure Tool an identical set of data is presented. One of the
    values is Perimeter. The calculated value is actually 2*PI*diameter.
    What the heck is this?

    The definition that Solidworks uses for Perimeter is the sum of the
    outer bounding edges. The definition that is used in all Geometry
    Texts is the sum of all outer bounding edges of a two-dimensional
    shape.

    My request is that they remove the Perimeter value if this selection is
    chosen. Is there anyone else that would agree?
     
    waligora, Dec 9, 2004
    #1
  2. waligora

    CS Guest

    I agree that it would be easy to overlook that it is calculating both edges.
    What you are looking for is it's circumference correct. Maybe they just
    need a change in terminology.
    Perimeter could be

    Total length of edges:

    and I think it would be beneficial to add

    Circumference:

    You have to remember that not all cylinders have square bottoms. And who is
    to actually say which end you would want to use as the Perimeter.

    Corey
     
    CS, Dec 9, 2004
    #2
  3. The perimeter of a sphere is 0.000", so at least they are consistent. I
    would rather have consistency then ask them to write exceptions for
    different geoemetry - that seems like we'd just be begging for trouble.
    But I see the point about the confusion - a square with a hole in the middle
    of it has a larger perimeter than the square itself, and I think I might
    make a bad assumption if I wasn't paying attention.

    If you are going to go into enhancment requests, I like Corey's suggestion
    of changing the term to 'total length of edges' because that is what is
    measured. <Maybe> its worth adding the possbility of adding a second
    'perimeter' calcuation that would only apply to outer loops of a face. Much
    of hte time, perimeter would be the same as total length of edges.
    Cylinders, spheres, and other similar shapes would deliver a perimeter of
    'n/a'

    Anyway, neat observation!
     
    Edward T Eaton, Dec 10, 2004
    #3
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.