Ellipsoid

[lab2010]

What is the best method to create an ellipsoid? I am trying to add an "end-cap" to a cylinder. For example the longitudinal axis of the cylinder is in the x direction. The cross-section of the cylinder is circular with radius r in the y-z plane. I have attached a simple sketch of what I would like to accomplish with an ellipsoidal end of dimensions r x r x 1/2*r.

I can make a semi-circle at the end of the cylinder in the y-z plane. By revolving that semi-circle sketch about the z axis, I get a spherical end-cap. The end-cap then extends a distance r beyond the cylinder edge instead of 1/2 * r. By creating an ellipse in the x-z or x-y planes and revolving, I get an end of dimensions r x 1/2*r x 1/2*r. This doesn't completely cover the cross-section of the cylinder. It doesn't seem like this shape can be created by revolving a sketch?

I am not an experienced CAD user. I am next going to try using some sort of surface by creating a guide, but I wanted to get some recommendations from more experienced users of the best method. I imagine this is a fairly common occurrence. Thanks in advance.

 

[JohnRBaker]

What version of NX are you using? Starting with NX 8.0 you can now create Edge (and Face) Blends using a Conic cross-section. I other words, this is now as simple as creating an Edge Blend.

As for your sketch approach, that should work as well, just create a single quadrant (0 to 90 degrees) of your ellipse and rotate that.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
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To an Engineer, the glass is twice as big as it needs to be.

 

[lab2010]

Roger.

I am currently using NX-6 waiting for the NX-8 procurement to go through. Once I get the updated software, I will try your recommendation.

Thanks!

 

[JohnRBaker]

Attached is an example, created in NX 6.0, of a model like you're trying to create using a sketch.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[mmauldin]

Another way to skin this particular cat. I created a sphere at the end of a cylinder then scaled the sphere in one direction by a .5 scale factor (the x direction in this case).

Picture only attached as it it done in 7.5

 

[John2025]

John,
Can you show an example of how to do it with a conic blend? I'm probably being dense, but I can't seem to figure it out.
We use NX8.5, FWIW.

 

[JohnRBaker]

Actually the Edge Blend didn't work out so well, but I came 'close' using a Conic Face Blend (see attaced).

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[John2025]

Very nice. Plus the shape can be easily tweaked with Rho.
Thanks