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Spline equation

Spline equation

Spline equation

(OP)
Hello guys

I'm wondering if it is possible to get the spline equation created in NX.
Does anyone know something about this?

RE: Spline equation

Using NX/Open or SNAP functions, you can get the degree of a spline and its poles (control points) and knots. Then, if you know about b-splines, you can write down its equation.

RE: Spline equation

(OP)
It isn't what I was expecting, but thanks for the response. ;)

RE: Spline equation

Quote (BubbaK)

Using NX/Open or SNAP functions, you can get the degree of a spline and its poles (control points) and knots.

You can also get this from the Information -> spline command.


blazejpop,
If you were expecting a simple polynomial equation such as 3x^2+4x-1, then you will be disappointed. A NURBS curve is actually composed of several equations blended together. If NX were to report the equation used it would look more like what you see on the Wikipedia page (in the General form of a NURBS curve section, about 3/4 way down the page).

www.nxjournaling.com

RE: Spline equation

(OP)
Hello.

I thought that spline is just spline, not B-spline or NURBS.

Thanks for your response.

RE: Spline equation

Quote (NX help CAD -> modeling -> curve -> spline)

All splines created in NX are Non Uniform Rational B-splines (NURBS).

www.nxjournaling.com

RE: Spline equation

The Wikipedia page is a good reference.

You will see that the general equation of the spline involves some things called basis functions. To construct these, you need some numbers called "knots" (or, collectively, the "knot vector" or "knot sequence").

As far as I know, you can't get the knots from within interactive NX, you have to use SNAP or NX/Open. You can get "knot points" from Information --> Spline, but knots and knot points are not the same thing. The former are numbers, and the latter are points.

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