def offsetPolyline(_polylineGUID, _offsetDistance):
# works for CONVEX
# offset direction is inwards
# parameters:
# _polylineGUID
# _offsetDistance
#
# version: 2012/07/05A
name = "offsetPolyline"
debug = False
# EVALUATION
doc = scriptcontext.doc
obj = doc.Objects.Find(_polylineGUID)
if obj == None:
print(name + ": No Object")
crv = obj.CurveGeometry
if not crv.IsPolyline():
print(name + ": Curve is not polyline")
return None
if not crv.IsClosed:
print(name + ": Curve is not closed")
d = crv.PointAtEnd.DistanceTo(crv.PointAtStart)
return None
L = []
pts= rs.CurvePoints(_polylineGUID)
for i in range((len(pts)-1)):
#print("")
iP = (i-1) % (len(pts)-1)
iC = (i+1) % (len(pts)-1)
iN = (i+2) % (len(pts)-1)
#print(str(iP) + " " + str(i) + " " + str(iC)+ " " + str(iN))
v1 = rs.VectorCreate(pts[iP], pts[i])
v2 = rs.VectorCreate(pts[iN], pts[iC])
a1 = rs.VectorAngle(v1,v2)
a2 = rs.VectorAngle(rs.VectorReverse(v1),v2)
if a1 < a2:
if debug:
print(str(a1) + " < " + str(a2))
# use first
else:
v1 = rs.VectorReverse(v1)
if debug:
print(str(a2) + " < " + str(a1))
# use second
v = ((v1[0] + v2[0])/2, (v1[1] + v2[1])/2,(v1[2] + v2[2])/2)
vY = rs.VectorUnitize(v)
vX = rs.VectorCreate(pts[i], pts[iC])
vZ= rs.VectorCrossProduct(vX, vY)
ptMid = ((pts[i][0] + pts[iC][0])/2, (pts[i][1] + pts[iC][1])/2, (pts[i][2] + pts[iC][2])/2)
p = rs.PlaneFromNormal(ptMid, vZ, vX)
#DEBUG
if debug:
Draw.drawPalneAxeAndArrows(p, _offsetDistance)
# make sure green arrawsa are pointing inwards
ptA = movePoint(pts[i], rs.VectorScale( rs.VectorUnitize( p[2] ), _offsetDistance))
ptB = movePoint(pts[iC], rs.VectorScale( rs.VectorUnitize( p[2] ), _offsetDistance))
ln = rs.AddLine(ptA, ptB)
L.append(ln)
P = []
for i in range(len(L)):
lineAPts = lineEndPoints(L[i])
lineBPts = lineEndPoints(L[(i+1) % len(L)])
intersection = rs.LineLineIntersection((lineAPts[0], lineAPts[1]), (lineBPts[0],lineBPts[1]))
ptI = intersection[0]
P.append(ptI)
rs.DeleteObjects(L)
P.append(P[0])
return rs.AddPolyline(P)
