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Perimeter of a Cylinder

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?

Reply to
waligora
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snipped-for-privacy@afc-holcroft.com wrote in news:1102623296.029879.186990 @f14g2000cwb.googlegroups.com:

It IS 2-dimensional, just not in a flat space. This makes sense, and I think the current behaviour should be kept, rather than removing the capacity. Perhaps change "perimiter" to "length of all edge loops" to emphasize the difference.

Reply to
Dale Dunn

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

Reply to
CS

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. 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!

Reply to
Edward T Eaton

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