Recursive triangulation in RhinoPython

17 Jul Recursive triangulation in RhinoPython

This recursive scripts generates a tree-like structure based on a simple algorithm. Each branch creates four sub-branches in the next level, making it very easy to multiply geometry in an exponential manner. Be careful as it does not provide sufficient error-checking, it simply assumes that you input the correct geometry.

#brocoli subdivision

#script written by Adolfo Nadal

#import libraries

import rhinoscriptsyntax as rss

import random

 

tmpSrfList = []

#define our function

def subdivideTriaSurf(srf,delete,scFactor):

    #duplicate border->returns a list

    #in this case we know we only want to have the first object [0]

    polyBorderList = rss.DuplicateSurfaceBorder(srf,1)

    polyBorder = polyBorderList[0]

    

    #test

    print (polyBorder)

    

    #get segments from the border as individual curves (helps get the middle points)

    segments = rss.ExplodeCurves(polyBorder)

    segment1 = segments[0]

    segment2 = segments[1]

    segment3 = segments[2]

    

    len = rss.CurveLength(segment1)

    

    #calculate middle points

    midPt1 = rss.CurveMidPoint(segment1)

    midPt2 = rss.CurveMidPoint(segment2)

    midPt3 = rss.CurveMidPoint(segment3)

    

    #calculate vertex

    vertexPts = rss.CurvePoints(polyBorder)

    pt1 = vertexPts[0]

    pt2 = vertexPts[1]

    pt3 = vertexPts[2]

    

    #calculate normal vector

    normVec = rss.SurfaceNormal(srf,(0,0))

    #scaleSurfaceNormal BEFORE ADDING

    normVec = rss.VectorScale(normVec,len*scFactor)

    

    #since normal vector is BY DEFAULT 0-based, we add it to the midPoints

    #to obtain the normals

    midPt1N = rss.VectorAdd(normVec,midPt1)

    midPt2N = rss.VectorAdd(normVec,midPt2)

    midPt3N = rss.VectorAdd(normVec,midPt3)

    

    “””

    rss.AddPoint(midPt1N)

    rss.AddPoint(midPt2N)

    rss.AddPoint(midPt3N)

    “””

    

    #add surfaces to the model

    baseSrf = rss.AddSrfPt((midPt1N,midPt2N,midPt3N))

    triaSrf1 = rss.AddSrfPt((pt1,midPt1N,midPt3N))

    triaSrf2 = rss.AddSrfPt((pt2,midPt2N,midPt1N))

    triaSrf3 = rss.AddSrfPt((pt3,midPt3N,midPt2N))

    

    #add control for further subdivision

    

    if(len>5):

        subdivideTriaSurf(baseSrf,delete,scFactor)

        subdivideTriaSurf(triaSrf1,delete,scFactor)

        subdivideTriaSurf(triaSrf2,delete,scFactor)

        subdivideTriaSurf(triaSrf3,delete,scFactor)

        tmpSrfList.append(baseSrf)

        tmpSrfList.append(triaSrf1)

        tmpSrfList.append(triaSrf2)

        tmpSrfList.append(triaSrf3)

        if(delete==”Yes”):

            rss.DeleteObjects((baseSrf,triaSrf1,triaSrf2,triaSrf3))

    

    rss.DeleteObject(polyBorder)

 

#obtain geometry

userSrf = rss.GetObject(“Please select your surface AND make sure that it needs to be defined by 3 points”,8)

 

#obtain other variables

userDelete = rss.GetString(“Do you want to delete the temp surfaces?, you can alway s do it later”,None,(“Yes”,”No”))

print userDelete

scaleFactor = rss.GetReal(“Please enter non-zero scale factor”,0.25,0.1,5)

 

#call the function

subdivideTriaSurf(userSrf,userDelete,scaleFactor)

 

#ask the user to erase temp surfaces

if (userDelete==”No”):

    userDeleteAfter = rss.GetString(“Do you want to delete the temp surfaces?”,None,(“Yes”,”No”))

    if(userDeleteAfter ==”Yes”):

        rss.DeleteObjects(tmpSrfList)