Questions on the spline-related functions of Mathematica (BezierCurve[], BSplineCurve[], etc.).

learn more… | top users | synonyms

7
votes
1answer
167 views

Fixing Spline curves so as to not overlap with themselves - (Diagrams)

Statement of the problem: Conceptually, what I'm trying to achieve is pretty simple. I have some code that generates a set of diagrams from a list of sets of points using BSplineCurve. Certain ...
19
votes
5answers
2k views

Implementation of smoothing splines function

I have some problems in writing a module for spline smoothing. Actually, I have been trying for about two weeks. My listing is here: ...
1
vote
1answer
251 views

BSplinefunction and its derivative

Hi I am trying to use curve fit some data using the BSplinefunction. I havent been using Mathematica long, so my questions might be quite basic. ...
11
votes
4answers
427 views

BSplineFunction derivatives wrong if using weights?

In my work, I make heavy use of non-uniform rational B-spline (NURBS) functions, defined using the function BSplineFunction[] with the option defining ...
3
votes
2answers
1k views

Generating x,y coordinates for an edge detection

I'd like to be able to process a number of graphics that have edge contours and output a list of $x$, $y$ coordinates to be used for generating a spline in another program, or in Mathematica, to make ...
1
vote
2answers
361 views

How to know form of plotted Bézier function

Simple scenario is to see the Bézier function, but how to know which polynomial approximate it? ...
13
votes
2answers
161 views

Is there a way to get BSplineFunction beyond MachinePrecision?

I have been using BSplineFunction (Mathematica 8) to generate a smooth representation of some data, which I might then do some further processing on. As I ...
14
votes
2answers
184 views

Color Blend in BezierCurve

How can I color a BezierCurve from Red into Green just as ...
8
votes
2answers
540 views
0
votes
1answer
436 views

Exporting B Spline Function to Excel

I am trying to export the data from a B Spline Function to a table in excel. I have tried exporting as many different file types (.xls, .txt, .dat), but all of them show up in excel as all of the ...
4
votes
3answers
1k views

Inverting a Spline-Function (Bezier or BSpline)

I would like to use a Spline-Function to describe a transformation from one range of reals to another, that is I would like to have a function which maps a value $y$ on $x$ and for simplicity let us ...
2
votes
2answers
327 views

Evaluating Polynomials at Grid Points

I am continuing my quest on B-splines. The code below builds a 5x5 matrix out of B-splines, using the BSplineBasis[] routine. I now want to evaluate the polynomials that are stored in each matrix ...
1
vote
0answers
387 views

Plotting derivatives of B-splines

I am trying to solve an electrodynamics problem numerically by using B-splines a basis function. Please don't ask me why, but if you really wanna know, here is the assignment. Using the following ...
3
votes
0answers
455 views

How to make 3D object smooth?

This thread considers mathematical methods here to make the 3D object smooth but this question consider how to achieve the goal of smoothing a 3D object in Mathematica. I want to get smoother ...
4
votes
0answers
447 views

Cubic polynomial interpolation with velocities listed rather than some points

I am trying to use the function BSplineFunction[] to create a natural cubic spline. Normally what is done is that you specify "SplineDegree -> 3" and include a list of points and it will carry out ...
3
votes
2answers
875 views

Parametric differentiable interpolation of a 2D data set

I have a set of data ...
6
votes
2answers
386 views

Convert BSplineFunction into two Interpolating Functions

Is there a way to decompose a BSplineFunction output into two functions x[t], y[t] ...
2
votes
3answers
200 views

How can I find the points of B Spline functions for a specific range?

Based on this question: I have a list of bspline functions (nearly 1000) provided by applying BSplineFunction to a list of points. I want to get the points each of ...
1
vote
2answers
816 views

Derivative of a spline approximation

To approximate an experimental data function $f(t)$ with $t \in (t_{min},t_{max})$ I used a cubic spline $s(p)=(t(p),f(p))$ with the parameter $p \in (0,1)$ and $p = t/(t_{max}-t_{min})$ by using the ...
6
votes
1answer
522 views

BSplineCurve Interpolation

Can I get interpolated values from this B-spline, (shown in red)? ...
26
votes
2answers
3k views

Joining and interpolating data points

I wonder what is the best practice for interpolating curves? Usually I'm using BSplineCurve and adjusting SplineWeights so it ...
12
votes
1answer
2k views

Fitting a spline to data with FindFit?

I am trying to find a function that fits my almost linear data. A high order polynomial model has too much residual. So I was hoping to use Mathematica to fit splines to the curve. This is what I ...
9
votes
1answer
266 views

SplineDegree->1 does not work with BezierFunction?

This works (SplineDegree -> 2) ...