Conic Surface Input

I need to input a conic surface (hyperbola) into SW. I have been
searching for a way to do this by inputting the vertex radii and the
conic constant, but there dosent seem to be a direct way to enter this
into SW.

I know about the xyz point table file which is an indirect method I
might use if nothing else works.

Has anyone found a way to input a conic surface by entering the vertex
radii and conic constant?

The conic constant is an optics term which is equal to the negative of
the eccentricity squared - FYI

Michael

 

I have seen posts byt others trying to make hyperbolae. The best
analytic solution I have seen was to make a cone surface and intersect
it with a plane. Good luck dialing in the particulars, though.

 

Is this supposed to be 100% accurate or just a representation? In other
words is it to be CNC machined or made another way?

I can give a method to construct a hyperbola.

TOP

 

It sounds like you have an equation to work from, input the equation
into Excel and generate a series of points. Then use the Curve Through
XYZ Points to insert the point file. Last time I did this (SW 2005) I
was not able to use the curve directly, I had to Convert it into
another sketch and then create the feature. I was creating demo
geometry for a Calculus class so I had the equation and limits to
start and stop the curve. With the current functionality in the 3D
Sketch you might be able to utilize those tools as well.

 

Sorry, just caught the XYZ reference in you post. My bad.

 

One other thought, have you looked at the Sketch Tool, Parabola and
mirroring it across a center line?

 

Thanks to all for the answers.

Yes is has to be accurate it will be single point diamond turned.
I did the xyz output table in the xy plane with z=0 and this worked to
get my curve in SW.
It would be best if SW had a way to input vertex radii and then a
conic constant and then one could draw any of the conics - sphere,
ellipse, hyperbola, and parabola.
Michael

 

<GAK>
For any exact (within computational limits) conic you need
very few points (5) or 3 points and two tangents but you do need
control of the degree.

 

That's why using the curve-thru-points or a spline will be flawed. SW
does not allow or control of degree. With the extra degree, a spline
weaves in and out of the conic curve between defning points, even with
tangent and curvature control.

 

From Google's cache (subject to change):
http://72.14.205.104/search?q=cache...+conic+cad&hl=en&ct=clnk&cd=10&gl=us&ie=UTF-8
(Doc of the UG GRIP programming language "BSURF/CONSRF" command/statement.)
What degree(s) does SW support? You only need second degree for planar conics
(but that's the same a cubic+ with zero for some coefficeients).

 

Note that for best accuracy it might be best to create such
symetric about the default CAD axis system and, if/when possible,
with integer values for given coordinate data and then do any
needed transforms on the CAM side with a fixture offset or
WCS/MCS. Avoid rotations if at a possible.

Another simple option might be to write the needed conic as
a short IGES file & import it.
http://www.iges5x.org/wysiwyg/f104x.shtml