Houdini 16.5 Nodes VOP nodes

Spline VOP node

Computes either a Catmull-Rom (Cardinal) spline or a Linear spline between the specified key points, given an interpolant (u) in the domain of the spline.

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This operator computes either a Catmull-Rom (Cardinal) spline or a Linear spline between the specified key points, given an interpolant (u) in the domain of the spline. The result is a 1D, 3D, or 4D value representing u’s image on the spline.

The Cardinal keys are uniformly spaced over the range 0 to 1. Because of the nature of the Cardinal spline, the value associated with the first and last keys will never be returned. However, these keys are used to determine the shape of the curve on entry and exit. If you want the spline to reach its end points, connect the first key and last key twice. See the Fire operator for one such example.

If you are blending only two vector types using the Cardinal interpolant, the Color Mix operator offers the convenience of fewer connections. Make sure, however, that you choose the Smooth With Cardinal Spline option to obtain the exact same results as with this operator.

The Linear spline interpolation is equivalent to a sequence of Linear Interpolation operators. Consider the simpler Mix operator if only two inputs are required.

Parameters

Spline

Catmull-Rom (Cardinal) or Linear.

Inputs

Parametric Coordinate

Interpolant (u) representing the parametric location in the domain of the spline where to evaluate the spline.

Input Number 1…N

1D, 3D or 4D spline key points to interpolate.

Next Input

Where the next key value should be connected. Up to 64 inputs can be specified.

Outputs

Combined Value

Interpolated spline location.

See also

VOP nodes