Closest Axis Point
This guide demonstrates how to find the closest point on a planar curve to an axis.
You have a bunch of 2-D curves that are planar to the world x-y plane, and you need to find a point in each curve that is closest to the world y-axis. For example:
What can you do to calculate this point?
After selecting the curves and verifying that they are both planar and line in the world x-y plane, calculate the world axis-aligned bounding box for each curve. Using the results of the bounding box calculation, create a line, using the first two points from the results, that is parallel to the world y-axis. Intersect this line with the curve. The results of the intersection will be at the point that is closest to the world y-axis.
The following example demonstrates the above algorithm…
Option Explicit Sub ClosestAxisPoint Dim arrCurves arrCurves = Rhino.GetObjects("Select planar curves", 4, True, True) If Not IsArray(arrCurves) Then Exit Sub Dim strCurve, arrPlane(3), arrBox, strLine, arrCCX arrPlane(0) = Array(0,0,0) arrPlane(1) = Array(1,0,0) arrPlane(2) = Array(0,1,0) arrPlane(3) = Array(0,0,1) Rhino.EnableRedraw False For Each strCurve In arrCurves If Rhino.IsCurvePlanar(strCurve) Then If Rhino.IsCurveInPlane(strCurve, arrPlane) Then arrBox = Rhino.BoundingBox(strCurve) strLine = Rhino.AddLine(arrBox(0), arrBox(1)) arrCCX = Rhino.CurveCurveIntersection(strCurve, strLine) If IsArray(arrCCX) Then Rhino.AddPoint arrCCX(0,1) End If Rhino.DeleteObject strLine End If End If Next Rhino.EnableRedraw True End Sub