Adaptive Plot Curve

Functionality

Given a Curve object, this node generates a mesh representing the curve. This way, it is similar to “Evaluate Curve” node with “Auto” mode. But, this node tries to generate less points for more “straight” parts of the curve, and more points for the most interesting parts of the curve. This way, the node is similar to “Adaptive Tessellate Surface” node.

The following algorithm is used:

• The whole domain of curve’s T parameters is subdivided into even parts.

• Then some points are added into “most interesting” intervals. “Interesting” can be defined as:

  • Having greater length;

  • Having bigger curvature value.

  Number of points to be added into each subdivision is calculated proportionally to this “subdivision factor”. These additional points can be distributed either evenly (in terms of curve’s T parameter), or randomly.

• Then all resulting points are connected to make a curve-like mesh object.

For NURBS and NURBS-like curves, consider use of “Adaptive Plot NURBS Curve” node.

• Generator-> Random Vector

• Curves-> Cubic Spline

• Viz-> Viewer Draw Curve

• Viz-> Viewer Draw

Inputs

This node has the following inputs:

• Curve. The curve to be plotted. This input is mandatory.

• Segments. Number of initial subdivisions. The default value is 25.

• Min per segment. This input is only available if Points Count parameter is set to Per Segment. Minimal number of additional points, which is to be added into intervals which have the least value of subdivision factor (length and/or curvature). The default value is 0 - do not add points to such intervals.

• Max per segment. This input is only available if Points Count parameter is set to Per Segment. Maximum number of additional points, which is to be added into intervals which have the greatest value of subdivision factor (length and/or curvature). The default value is 5.

• Count. This input is only available when Points Count parameter is set to Total Count. Total number of points to be generated. NOTE: when Random parameter is checked, actual number of points generated by this node can be less than the value provided in this input. The default value is 50.

• Seed. Random seed value. This input is only available when the Random parameter is enabled. The default value is 0.

Parameters

This node has the following parameters:

• By Curvature. Use curve curvature value to distribute additional points on the curve: places with greater curvature value will receive more points. Checked by default.

• By Length. Use segment lengths to distribute additional points on the curve: segments with greater length will receive more points. Unchecked by default.

  

• Points Count. This defines how number of points to be generated will be defined. Possible options are:

  • Total Count. Total number of points to be generated will be provided in the Count input.

    

  • Per Segment. Minimum and maximum number of points per initial subdivision segment will be provided in Min per segment, Max per segment inputs, correspondingly.

  The default option is Total Count.

  

• Random. If checked, then additional points will be distributed randomly. Otherwise, additional points will be distributed evenly inside each segment of initial subdivision. Unchecked by default.

• Curvature Clip. This parameter is available only in the N panel of the node, only when the By Curvature parameter is enabled. The calculated values of curve curvature will be restricted to do not exceed this number. This is used to ignore places on the curve where it has too high values of curvature (sharp points) - otherwise the algorithm would be placing all the additional points to such places. The default value is 100. Usually you do not have to change this value. Set the parameter to 0 (zero) to disable this part of the algorithm.

  

Outputs

This node has the following outputs:

• Vertices. The vertices of the generated mesh.

• Edges. The edges of the generated mesh.

• T. Values of curve’s T parameter for all generated points on the curve.