Skip to main content
24-Ruby IV
January 1, 2020
Solved

Cone, plane, ellipse

  • January 1, 2020
  • 2 replies
  • 5661 views

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

Cone.png

Best answer by ptc-5737066

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.

2 replies

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

24-Ruby IV
January 2, 2020

Thanks!

For a of a circular cone too?

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.

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.