Evaluate Spline

Description

This node will return the position and the tangent line of a point on the curve at some normalized distance from the starting point where this distance is defined by the input Parameter.

../../../_images/evaluate_spline_node.png

Options

  • Uniform - This option samples the points regardless of the geometry of the spline.
  • Resolution - This option samples the points based on the geometry of the spline.

To understand this better lets look at the following example:

../../../_images/uniform_vs_resolution_interpolation.png

The above example shows 2 identical splines where the upper one uses Uniform and the other uses Resolution. If one were to sample some points at regular intervals on both splines, He would observe that:

  • Points on Uniform are regularly distributed.
  • Points on Resolution are dense at some areas and spaced at others.

So we notice that Resolution care about the geometry of the spline and so a regularly spaced parameters will be closer at parts of the spline where it has dense geometry and spaced at relaxed parts.

Uniform on the other hand will yield results based on the actual distance along the spline, however, it is much slower to compute.

Inputs

  • Spline - A spline to evaluate.
  • Parameter - The position of the point to be evaluated in the normalized distance of the spline. (0 is the start of the spline and 1 is the end of the spline)

Outputs

  • Location - A vector that represents the position of the point in the curve that correspond to the input parameter.
  • Tangent - A vector that is aligned with the tangent line to the evaluated point.

Advanced Node Settings

  • Resolution - It is the quality of the evaluated spline, in other words, it is the number of point in the spline used in evaluation.

Examples of Usage

../../../_images/evaluate_spline_node_example.gif