adding the reflection method.

reflection.py

# -*- coding: utf-8 -*-

import rhinoscriptsyntax as rs
import Rhino.Geometry.Vector3d as vec3d

def VectorReflection(_vector,_normal):
    '''
    反射ベクトルを求める
    '''
    n = rs.VectorUnitize(_normal)
    dot = rs.VectorDotProduct(n,_vector)
    
    return -2 * dot * n +_vector
    
def MeshReflection(_mesh,_line):
    
    intersections = rs.CurveMeshIntersection(_line,_mesh,True)
    if intersections is None: return None
    
    sp = rs.CurveStartPoint(_line)
    dist = 99999999999999.99
    for i in intersections:
        tempDist = rs.Distance(sp,i[0])
        if tempDist < dist :
            dist = tempDist
            nearest = i
    
    meshNormals = rs.MeshFaceNormals(_mesh)
    mn = meshNormals[nearest[1]]
    
    vec = rs.CurveEndPoint(_line) - sp
    
    return nearest[0],VectorReflection (vec,mn)
    
def MeshBounce(_mesh,_line,_length=None):
    
    mr = MeshReflection(_mesh,line)
    if mr is None : return None
    
    sp = mr[0]
    if _length is None :
        ep = sp + mr[1]
    else:
        d = rs.VectorScale(rs.VectorUnitize(mr[1]),_length)
        ep = sp + d
        
    return rs.AddLine(sp,ep)
    
if __name__ == '__main__':
    line = rs.GetObject('line')
    mesh = rs.GetObject('mesh')
    
    bounce = MeshBounce(mesh,line)