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ValeryOchkov24-Ruby IV
24-Ruby IV
January 1, 2020
Solved

Cone, plane, ellipse

I know a and b of an ellipse. What is the value alpha of a circular cone?

Cone.png

ptc-5737066Answer
1-Visitor
January 2, 2020

Yes,

N.png

here is example when a=15, b=8 and alpha=30 degree...

N2.png

..and when alpha changes to 40 degree

Observe that auxiliary view is normal to cutting plane and does not show real cone angle.

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11 replies

ptc-57370661-Visitor
1-Visitor
January 2, 2020

a & b are not sufficient to define alpha.

No mather what alpha you have, you can allways slice cone to obtain ellipse with dimmensions a & b.

/Avdo

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    ValeryOchkov24-Ruby IVAuthor
    24-Ruby IV
    January 2, 2020

    Thanks!

    For a of a circular cone too?

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    ptc-57370661-VisitorAnswer
    1-Visitor
    January 2, 2020

    Yes,

    N.png

    here is example when a=15, b=8 and alpha=30 degree...

    N2.png

    ..and when alpha changes to 40 degree

    Observe that auxiliary view is normal to cutting plane and does not show real cone angle.

    Translate
      -MFra-21-Topaz II
      21-Topaz II
      January 4, 2020

      Hi,

      With the use of analytical geometry and with the data available, this is all you can do:

      Risposta a V. O..jpg

      Happy New Year.

      F. M.

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