Bezier Constructor

💻 Rhino 5

🔼 Rhino Script

🛠️ Visual Basic

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This rhinoscript takes a series of points selected in sequence and creates a bezier curve using the geometric method of construction. Rendering both the final bezier curve as well as the construction lines used to produce this curve. These curves produce a beautiful spatial fabric in visualizing the geometric structure beneath. A more detailed/ animated reference of this method of construction can be found at Wikipedia

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Option Explicit 
'Script written by <David Mans> 
'Script copyrighted by <Neoarchaic Design> 
'Script version Tuesday, July 21, 2009 7:50:34 PM 
Call Main() 
Sub Main() 
    Dim arrPoints,intSamples 
    Do
        arrPoints = Rhino.GetObjects("Select at Least 3 Points", 1,, True) 
        If isNull(arrPoints) Then Exit Sub
        If uBound(arrPoints) > 1 Then
            Exit Do
        End If
    Loop
    intSamples = Rhino.GetReal("Samples", 10, 1) 
    If isNull(intSamples) Then Exit Sub
    Dim i, arrPts(),arrOutput 
    ReDim arrPts(uBound(arrPoints)) 
    For i = 0 To uBound(arrPoints) Step 1 
        arrPts(i) = Rhino.PointCoordinates(arrPoints(i)) 
    Next
    Call Rhino.EnableRedraw(False) 
    arrOutput = bezierConstructor(arrPts, intSamples) 
    Call Rhino.AddInterpCurve(arrOutput(0)) 
    Call Rhino.ObjectColor(arrOutput(1), RGB(255, 0, 0)) 
    Call Rhino.EnableRedraw(True) 
End Sub
Function bezierConstructor(arrPts, intSamples) 
    bezierConstructor = Null 
    Dim i, j, k, r, s, t 
    Dim arrOutput(), arrOutputs(), arrStore, arrTemp, arrLines(),arrSet() 
    r = 0 
    k = 1 
    ReDim arrOutput(0),arrOutputs(0) 
    arrOutput(0) = arrPts(0) 
    For i = 1 To uBound(arrPts) Step 1 
        ReDim Preserve arrLines(r),arrOutputs(r) 
        arrLines(r) = Rhino.AddLine(arrPts(i - 1), arrPts(i)) 
        arrOutputs(r) = arrLines(r) 
        r = r + 1 
    Next
    t = r 
    arrStore = arrLines 
    For i = 1 To intSamples - 1 Step 1 
        r = 0 
        s = 0 
        arrTemp = arrStore 
        Do
            If r = 1 Then
                ReDim Preserve arrOutput(k) 
                arrOutput(k) = curveParameter(arrTemp(0), i * (1 / intSamples)) 
                k = k + 1 
                Exit Do
            End If
            r = 0 
            ReDim Preserve arrSet(s) 
            arrSet(s) = arrTemp 
            ReDim arrLines(0) 
            For j = 1 To ubound(arrSet(s)) Step 1 
                ReDim Preserve arrLines(r), arrOutputs(t) 
                arrLines(r) = Rhino.AddLine(curveParameter(arrSet(s)(j - 1), i * (1 / intSamples)), curveParameter(arrSet(s)(j), i * (1 / intSamples))) 
                arrOutputs(t) = arrLines(r) 
                t = t + 1 
                r = r + 1 
            Next
            arrTemp = arrLines 
            s = s + 1 
        Loop
    Next
    ReDim Preserve arrOutput(k) 
    arrOutput(k) = arrPts(uBound(arrPts)) 
    bezierConstructor = array(arrOutput, arrOutputs) 
End Function
Function curveParameter(strCurve, dblParameter) 
    curveParameter = Null 
    Dim cDom,arrPoint 
    cDom = Rhino.CurveDomain(strCurve) 
    arrPoint = Rhino.EvaluateCurve(strCurve, cDom(0) + dblParameter * (cDom(1) - cDom(0))) 
    curveParameter = arrPoint 
End Function

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