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CatmullRomSpline Class Reference

An implementation of Catmull-Rom splines (sometimes known as Overhauser splines). More...


Detailed Description

An implementation of Catmull-Rom splines (sometimes known as Overhauser splines).

In this implementation, the end tangents are created automatically by reflection.

In matrix form, the local interpolation on the interval t=[0..1] is described as follows:

P(t) = 1/2 * [ t^3 t^2 t 1 ] * [ -1  3 -3  1 ] * [ P-1 ]
   [  2 -5  4 -1 ]   [ P0 ]
   [ -1  0  1  0 ]   [ P1 ]
   [  0  2  0  0 ]   [ P2 ]

Where P-1 and P2 represent the neighbouring points or the extrapolated end points. Simple reflection is used to automatically create the end points.

The spline is discretized based on the chord length of the individual segments. In rare cases (sections with very high curvatures), the resulting distribution may be sub-optimal.

See also:
http://www.algorithmist.net/catmullrom.html provides a nice introduction
Todo:
A future implementation could also handle closed splines.
Source files

Definition at line 77 of file CatmullRomSpline.H.

+ Inheritance diagram for CatmullRomSpline:
+ Collaboration diagram for CatmullRomSpline:

List of all members.

Public Member Functions

 CatmullRomSpline (const pointField &knots, const bool notImplementedClosed=false)
 Construct from components.
point position (const scalar lambda) const
 Return the point position corresponding to the curve parameter.
point position (const label segment, const scalar lambda) const
 Return the point position corresponding to the local parameter.
scalar length () const
 Return the length of the curve - not implemented.
- Public Member Functions inherited from polyLine
 polyLine (const pointField &, const bool notImplementedClosed=false)
 Construct from components.
const pointFieldpoints () const
 Return const-access to the control-points.
label nSegments () const
 Return the number of line segments.

Additional Inherited Members

- Protected Member Functions inherited from polyLine
void calcParam ()
 Precalculate the rational cumulative parameter value.
label localParameter (scalar &lambda) const
 Return the line segment and the local parameter [0..1].
- Protected Attributes inherited from polyLine
pointField points_
 The control points or ends of each segments.
scalar lineLength_
 The real line length.
scalarList param_
 The rational (0-1) cumulative parameter value for each point.

Constructor & Destructor Documentation

CatmullRomSpline ( const pointField knots,
const bool  notImplementedClosed = false 
)

Construct from components.


Member Function Documentation

point position ( const scalar  lambda) const

Return the point position corresponding to the curve parameter.

0 <= lambda <= 1

Reimplemented from polyLine.

Reimplemented in splineEdge.

point position ( const label  segment,
const scalar  lambda 
) const

Return the point position corresponding to the local parameter.

0 <= lambda <= 1 on the given segment

Reimplemented from polyLine.

scalar length ( ) const

Return the length of the curve - not implemented.

Reimplemented from polyLine.

Reimplemented in splineEdge.


The documentation for this class was generated from the following file: