Parametric Conic

[dilluvcj]

Hi All!

Does anyone know how to create a parametric conic? I like all of the options under General Conic for creating them, but I can't tie them back to the construction geometry. Using the simplest example, if I create 5 points and build a conic thru them using the 5 Point option, I can't go back and edit the point location and have the conic update. I tried building a conic in sketcher as well with no luck.

 

[dilluvcj]

The other thing I forgot to mention is that I would like it if the conic would show up in the model history. I can pick it on the screen, but that could be cumbersome with bigger models. I also like to name my curves from time to time.

I am using NX 5.0.4.1 by the way.

 

[potrero]

Can you be more descriptive about how you went about trying to build your conic in Sketcher? Others may have had more luck than you, in this regard...

 

[dilluvcj]

No problem potero...maybe some screen images will help.

This first one shows the construction geometry I would like to use (two lines and a central point).

This second image shows what I get when I use General Conic outside of sketcher and build it using 3 Points, 2 Slopes. Exactly what I want....except, I can't edit my construction geometry and have the conic update. Plus, I sure wish the conic would show up in the history tree.

This last image shows what happens in sketcher. I can only select three points. When I try to constrain the conic in such a way so as to get what I want (tangent to the end lines and thru the center point), I end up overconstrained.

Chris Dilluvio
General Motors

 

[potrero]

Unfortunately I don't have NX5 anymore, but I definitely have not have problems doing what you're trying to do. Perhaps someone else can supply an example in NX5 for you.

 

[JohnRBaker]

Generally speaking, Conics in NX are neither Parametric nor even associative. The only exception is that in the Sketcher we support Ellipses and the '2 Points, Anchor, Rho' Conic. If you wish to create a true Conic (outside the Sketcher) and have it be fully Parametric (that is driven by expressions) you will need to employ the Law Curve function using formulas for conic profiles.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

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

 

[dilluvcj]

Understood John, that's what I figured. It would be nice to be able to make them associative with the construction geometry. I have need frequently to push & pull these conics until they give me the appearance I like.

 

[potrero]

If your needs can be served with the Conic inside Sketcher, then you definitely can have a parametric conic.

 

[dilluvcj]

I found a pretty simple workaround that gives me exactly what I need. The Insert-Mesh Surface-Section option brings up a wide array of conical surface options. For the example I posted in this thread, Fillet-Shoulder works nicely. I built a short conical surface that I can tie back to a sketch. I can then use an edge of this concial surface as my associative conic. In my application, I use this conic curve as a guide for a section drag. I can modify the sketch and the conical surface updates on the fly along with the conic curve and section drag.

 

[JohnRBaker]

Yea, I forgot about them. The 'Section Surface' function covers all of the normal general-conic methods and then some.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

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

 

[potrero]

@dilluvcj:
that's a neat idea. thanks for posting it.