Package org.jzy3d.maths.algorithms.interpolation.algorithms

Class Spline3D

java.lang.Object
org.jzy3d.maths.algorithms.interpolation.algorithms.Spline3D
public class Spline3D extends Object

This is a generic 3D B-Spline class for curves of arbitrary length, control handles and patches are created and joined automatically as described here: ibiblio.org/e-notes/ Splines/Bint.htm

Thanks to a bug report by Aaron Meyers (http://universaloscillation.com) the computeVertices(int) method has a slightly changed behaviour from version 0014 onwards. In earlier versions erroneous duplicate points would be added near each given control point, which lead to various weird results.

The new behaviour of the curve interpolation/computation is described in the docs for the computeVertices(int) method below.

Version:
0014 Added user adjustable curve tightness control, 0015 Added JAXB annotations and List support for dynamic building of spline

  • Field Details

    • DEFAULT_TIGHTNESS

      public static final float DEFAULT_TIGHTNESS
      See Also:

    • points

      protected Coord3d[] points

    • pointList

      public List<Coord3d> pointList

    • vertices

      public List<Coord3d> vertices

    • bernstein

      public BernsteinPolynomial bernstein

    • delta

      public Coord3d[] delta

    • coeffA

      public Coord3d[] coeffA

    • bi

      public float[] bi

    • tightness

      protected float tightness

    • invTightness

      protected float invTightness

    • numP

      protected int numP

  • Constructor Details

    • Spline3D

      public Spline3D()
      Constructs an empty spline container with default curve tightness. You need to populate the spline manually by using add(Coord3d).

    • Spline3D

      public Spline3D(List<Coord3d> rawPoints)
      Parameters:
      rawPoints - list of control point vectors

    • Spline3D

      public Spline3D(List<Coord3d> rawPoints, BernsteinPolynomial b, float tightness)
      Parameters:
      rawPoints - list of control point vectors
      b - predefined Bernstein polynomial (good for reusing)
      tightness - default curve tightness used for the interpolated vertices setTightness(float)

    • Spline3D

      public Spline3D(Coord3d[] pointArray)

    • Spline3D

      public Spline3D(Coord3d[] pointArray, BernsteinPolynomial b, float tightness)
      Parameters:
      pointArray - array of control point vectors
      b - predefined Bernstein polynomial (good for reusing)
      tightness - default curve tightness used for the interpolated vertices setTightness(float)

  • Method Details

    • add

      public Spline3D add(float x, float y, float z)

    • add

      public Spline3D add(Coord3d p)
      Adds the given point to the list of control points.
      Parameters:
      p -
      Returns:
      itself

    • computeVertices

      public List<Coord3d> computeVertices(int res)

      Computes all curve vertices based on the resolution/number of subdivisions requested. The higher, the more vertices are computed:

      (number of control points - 1) * resolution + 1

      Since version 0014 the automatic placement of the curve handles can also be manipulated via the setTightness(float) method.

      Parameters:
      res - the number of vertices to be computed per segment between original control points (incl. control point always at the start of each segment)
      Returns:
      list of Coord3d vertices along the curve

    • findCPoints

      protected void findCPoints()

    • getDecimatedVertices

      public List<Coord3d> getDecimatedVertices(float step)

    • getNumPoints

      public int getNumPoints()
      Returns the number of key points.
      Returns:
      the numP

    • getPointList

      public List<Coord3d> getPointList()
      Returns:
      the pointList

    • getTightness

      public float getTightness()
      Returns:
      the spline3d tightness
      Since:
      0014 (rev.216)
      See Also:

    • setPointList

      public Spline3D setPointList(List<Coord3d> plist)
      Parameters:
      pointList - the pointList to set

    • setTightness

      public Spline3D setTightness(float tightness)
      Sets the tightness for future curve interpolation calls. Default value is 0.25. A value of 0.0 equals linear interpolation between the given curve input points. Curve behaviour for values outside the 0.0 .. 0.5 interval is unspecified and becomes increasingly less intuitive. Negative values are possible too and create interesting results (in some cases).
      Parameters:
      tightness - the tightness value used for the next call to computeVertices(int)
      Since:
      0014 (rev. 216)

    • updateCoefficients

      public void updateCoefficients()