Thread Subject: Fitting a surface with Nurbs

Hello everyone,

I have the following problem. I have a surface and must perform a Nurbs (Non Uniform Rational B-Splines) fit of it. The question is how to do it.
Maybe it's a really dumb question but it's not totally clear to me how to optimize the knots/control points in order to minimize the fit error in the case of a general surface. I would be grateful for any pointers.

Thanks in advance,
Daniel.

Hi Daniel,
I am in a similar situation. Did you get any solution for your problem?
Farheen

"Daniel Arevalo" <daniarev@gmail.com> wrote in message <hc59vf$h6s$1@fred.mathworks.com>...
> Hello everyone,
>
> I have the following problem. I have a surface and must perform a Nurbs (Non Uniform Rational B-Splines) fit of it. The question is how to do it.
> Maybe it's a really dumb question but it's not totally clear to me how to optimize the knots/control points in order to minimize the fit error in the case of a general surface. I would be grateful for any pointers.
>
> Thanks in advance,
> Daniel.

"Daniel Arevalo" <daniarev@gmail.com> wrote in message <hc59vf$h6s$1@fred.mathworks.com>...
> Hello everyone,
>
> I have the following problem. I have a surface and must perform a Nurbs (Non Uniform Rational B-Splines) fit of it. The question is how to do it.
> Maybe it's a really dumb question but it's not totally clear to me how to optimize the knots/control points in order to minimize the fit error in the case of a general surface. I would be grateful for any pointers.
>
> Thanks in advance,
> Daniel.

Make one of them a constant value, for example keep the knots vector value and calculate the control points and its weights. Calculate the error usign euclidean distance, and try to get minimum error.