Questions tagged [splines]

Questions on the spline-related functions of Mathematica (BezierCurve[], BSplineCurve[], etc.), or related to the theory and use of splines in Mathematica.

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Solve a PDE over a region defined by a Bézier patch

I am using NDSolve to find the solution to a PDE over an arbitrary domain. The domain is specified by a Bézier patch. ...
251 views

Confusion with SplineFit (Angle calculation)

This question is a continuation to [this other one][1] I am creating polymers (where each monomer is of equal length) using this method: ...
616 views

How to specify PDE Boundary condition on a B-spline?

Context I would like to solve a PDE on a boundary which is parametrized as a BSpline. I am trying to solve the force-free Grad-Shafranov equation on a boundary ...
1 vote
93 views

Positive Change, Negative Change, and Total Change with Values on Graph

I am trying to show a change in cross-section geometry between years, and have good visual plots but would like actual values to use also. I am using spline curves to visualize the cross sections, ...
211 views

Coordinates of spline plot using ArcLength mesh function

The following code produces a 3D spline with equidistant interpolation points: ...
257 views

What do the arguments of a generated BSplineFunction mean?

For example, if we evaluate this: BSplineFunction@{{0,100},{200,50},{200,0}} we'll get ...
1 vote
128 views

Proper way to discretize a parametric spline surface

Given that I have a triangular mesh model defined in obj format (1590 vertices and 300 faces), I reconstruct it to a single B-spline surface. Now I want to export ...
77 views

How to integrate 2 compoonent spline function

I have a Spline function defined as follows. Points = {{0, 0}, {0, 1}, {1, 1}, {1, 0}, {0, 0}}; bsf = BSplineFunction[Points, SplineDegree -> 1]; A Parametric ...
95 views

Options to find an analytical description of some points

I have a set of points {{x1,y1},...{xn,yn}} and I would like to have the analytical expression of a function that describes them reasonably well. So that I can plot this function on a ...
53 views

Getting Log10 axis in Graphics Function

In the output shown in the following image, I need x axis to be logarithmic (base 10) instead of linear. When I used ListLogLinearPlot function I got scattered points instead of the required B Spline ...
84 views

How to NIntegrate multiple ranges of data at the same time with an output that can be plotted?

I am trying to use the NIntegrate function to find the difference in the area beneath two 2 dimensional splines (how much area of the river bed was lost or gained from one year to the next) but, I ...
95 views

CaputoD of (Edge) BSplines

tl;dr Why does this works: CaputoD[BSplineBasis[{3, {0, 1, 2, 3, 4}}, 0, x], {x, 1/2}] // Simplify Whereas this fails ...
355 views

SplineDegree->1 does not work with BezierFunction?

This works (SplineDegree -> 2) ...
213 views

How to obtain the function of a plotted Bezier curve?

I have some control points and I could just plot the Bezier curve, but I also need to have the function! How can I get the exact function of the plotted Bezier curve?
280 views

BezierCurve is different from BezierFunction

I am constructing Naca type profiles with Bezier curves. ...
2k views

How to integrate a Bézier function?

I have: points = {{0, 100}, {250, 0}, {0, 300}, {500, 500}} And I want to know the area below the curve, so I came to: ...
267 views

Convert interpolating function to a Bezier curve

I've been wondering, is there a way to convert an interpolation into a sequence of BezierCurve objects that form each step in the interpolation? There is an easy ...
1 vote
98 views

Recurrence relation for B-spline polynomials

I am trying to get the explicit polynomials of cardinal B-splines. So far I have this implementation (for cardial B-splines of degree 3 on the knots 0, 1, 2, 3): ...
1 vote
134 views

How does Mathematica's B-Spline NURBS work?

I'm finding that Mathematica is getting hung up on a numerical integration and I suspect I can do it faster myself in C++. I can scoop the control points of the BSplineFunction out of the ...
348 views

Geogebra spline command in Mathematica

Spline(pts, order, Weight Function) Creates a spline with given order through all points. The weight function says what should be the difference of t values for point $P_i$ and $P_{(i+1)}$ given ...
1 vote
304 views

Cubic spline fitting

If I have the following data: ...
403 views

Understanding Interpolation with Cubic Splines

My ultimate question: given data, what function is Interpolation with Method->"Spline" creating? I recall from my ...
130 views

Closed BezierCurve is cut in exported PDF or EPS

Bug introduced in 10.3 or earlier and persisting through 11.1.0 or later Exporting the filled Bézier curve to PDF or EPS yields ...
136 views

Why FilledCurve and BezierCurve or BSplineCurve do not fit

I want to draw the outline of a circle (it's actually the glyph period from Cascadia Code font): ...
906 views

Convert BSplineFunction into two Interpolating Functions

Is there a way to decompose a BSplineFunction output into two functions x[t], y[t] ...
1 vote
101 views

Is task to find intersections of a line and a cubic Bezier curve really so hard?

I wrote formulas for parametric Bezier curves of different orders ...
141 views

BSplineFunction returns unevaluated when its degree is equal to the number of control points

Bug fixed in 13.0.0 [CASE:4855260] It seems that BSplineFunction always returns unevaluated without warnings, when its degree is equal to the number of control ...
217 views

143 views

How to draw a colored curved shape

I can draw a polygon with a curved edge using B-splines or Bézier curves: ...
229 views

Best parameter for smoothing splines

I am trying to implement a module to determine the best value for the smoothing parameter of a smoothing spline interpolation of a given dataset. To calculate the cross-validation score of a given ...