ChamferCorner.py

import rhinoscriptsyntax  as rs
import scriptcontext as sc
import Rhino

def ChamferCorner():
    tol = sc.doc.ModelAbsoluteTolerance
    def VertexFilter( rhino_object, geometry, component_index):
        
        if component_index.ComponentIndexType == Rhino.Geometry.ComponentIndexType.BrepVertex:
            return True
        return False
    while True:
        rad = 1
        if sc.sticky.has_key('VERTCHAMFER_RAD'):
            rad = sc.sticky['VERTCHAMFER_RAD']
            
        go=Rhino.Input.Custom.GetObject()
        
        go.SubObjectSelect = True
        go.BottomObjectPreference = True
        
        go.ChooseOneQuestion = True
        go.AcceptNumber(True, False)
        
        go.SetCommandPrompt("Select corner")
        go.SetCustomGeometryFilter (VertexFilter)
        
        opRad = Rhino.Input.Custom.OptionDouble(rad)
        go.AddOptionDouble('Setback', opRad)
        
        ret = go.Get()
        
        if go.CommandResult() != Rhino.Commands.Result.Success:
            return go.CommandResult()
            
        if ret == Rhino.Input.GetResult.Option:
            rad = opRad.CurrentValue
            sc.sticky['VERTCHAMFER_RAD'] = rad
            continue
            
        if ret == Rhino.Input.GetResult.Number:
            rad = go.Number()
            sc.sticky['VERTCHAMFER_RAD'] = rad
            continue
            
        if ret == Rhino.Input.GetResult.Object:
            break
    
    objref = go.Object(0)
    idx = objref.GeometryComponentIndex.Index
    pt = objref.Geometry().Location
    
    brep= sc.doc.Objects.Find(objref.ObjectId)
    geo = brep.Geometry
    
    edgeIdcs = geo.Vertices[idx].EdgeIndices()
    edges  = [geo.Edges[n] for n in edgeIdcs]
    
    crvs = [edge.ToNurbsCurve() for edge in edges]
    pts = []
    sph = Rhino.Geometry.Sphere(pt, rad).ToNurbsSurface()
    
    for crv in crvs:
        int = Rhino.Geometry.Intersect.Intersection.CurveSurface(crv, sph, tol, tol)
        if len(int) == 0:
            print "Can't find a needed intersection. The setback may be larger than the neighboring edge length."
            return
        pts.append(int[0].PointA)

    rc, plane = Rhino.Geometry.Plane.FitPlaneToPoints(pts)
    
    planePt = plane.ClosestPoint(pt)
    planeMid = plane.PointAt(.5,.5)
    
    vecDir = planePt-planeMid
    
    if plane.ZAxis.IsParallelTo(pt-planePt) == 1:plane.Flip()

    bb = Rhino.Geometry.BoundingBox(pts)
    intervalX = Rhino.Geometry.Interval(0, bb.Diagonal.Length)
    intervalY = Rhino.Geometry.Interval(0, bb.Diagonal.Length)
    
    planeBrep = Rhino.Geometry.PlaneSurface(plane, intervalX, intervalY).ToBrep()
    planeBrep.Translate(planePt - planeBrep.Faces[0].PointAt(intervalX.Mid,intervalY.Mid))

    bln = Rhino.Geometry.Brep.CreateBooleanDifference(geo, planeBrep, tol)
    
    if bln:
        sc.doc.Objects.Replace(objref.ObjectId, bln[0])
        
    sc.doc.Views.Redraw()

    
if __name__=='__main__':ChamferCorner()