Hi,
after I imported a FBX model I got a lot of buggy NURBS surfaces. Is there a quick way to repair them? My current workflow: _UntrimBorder → set _KeepTrimObjects=yes, choose surface and untrim. Now trim the clean surface with the border curve again.
I tried _RebuildEdges, but it doesn’t help. Is there an other command to do it in one step?
-Micha
In general, something like this;
Duplicate boundary curves.
Untrim surface.
Retrim surface using the boundary curves.
Here’s a quick py version…
RetrimSrf.py (1.4 KB)
To use the Python script use RunPythonScript, or a macro:
_-RunPythonScript "Full path to py file inside double-quotes"
-Pascal
Sorry, I should have read your entire post…
No problem, thanks for trying to help. 
Hi @pascal,
today I run in the situation again and try to repair the attached surface per script, but nothing happens. I have a lot of this surfaces in my model. Do you know a solution?
Best -
Micha
! _-RunPythonScript (
import Rhino
import rhinoscriptsyntax as rs
import scriptcontext as sc
import System.Collections.Generic.IEnumerable as IEnumerable
import System.Double as sd
"""
Get the 3d edge curves that you will be splitting with.
Reverse any that come from reversed trims.
Split with those curves.
Now the face that you want to keep will
not have any reversed trims.
"""
def RetrimSrf():
tol = sc.doc.ModelAbsoluteTolerance
id = rs.GetObject(filter = 8, preselect=True)
if not id: return
brep = rs.coercebrep(id)
bb = brep.GetBoundingBox(True)
face = brep.Faces[0]
edges = brep.Edges
trims = brep.Trims
crvs =[]
for i in range(edges.Count):
crv = edges[i].ToNurbsCurve()
if trims[i].IsReversed():
crv.Flip()
crvs.append(crv)
pass
x = trims[0].IsReversed()
srf = face.UnderlyingSurface()
temp = srf.ToBrep()
tFace = temp.Faces[0]
newBrep = tFace.Split(crvs, tol)
for brepFace in newBrep.Faces:
rev = False
for trim in brepFace.OuterLoop.Trims:
if trim.IsReversed():
rev = True
break
if rev:
continue
else:
sc.doc.Objects.Replace(id, brepFace.DuplicateFace(False))
sc.doc.Views.Redraw()
if __name__== '__main__':RetrimSrf()
)
InvisibleSurface.3dm (70.5 KB)
Hi Micha - it works here - here is the version of the script that I am using -
RetrimSrf.py (2.6 KB)
-Pascal
Hi Pascal,
thank you very much for your help. 
I started your latest script per
_-RunPythonScript "Full path to py file inside double-quotes"
and it works fine.
General I try to keep scripts within toolbar buttons (for easier update and transportation to new Rhino versions) and I wonder why your script doesn’t work if I copy the py code within () of this code. Do you see an aspect I have overseen - complete copy at the end of the post. This version makes nothing, no retrim, no messages and no errors.
Often only some surfaces of a polysurface needs a retrim. Could you modify the script for cleaning polysurfaces too please?
-Micha
! _-RunPythonScript (
import Rhino
import scriptcontext as sc
import rhinoscriptsyntax as rs
def BBCompare(BB1,BB2):
#BB2 = original
tol = sc.doc.ModelAbsoluteTolerance
x = BB1.Min.DistanceTo(BB2.Min)
#rs.AddPoints([BB1.Min,BB2.Min])
y = BB1.Max.DistanceTo(BB2.Max)
if BB1.Min.DistanceTo(BB2.Min)< tol:
if BB1.Max.DistanceTo(BB2.Max)< tol:
#print "BBTrue"
return True
return False
def MaxEdgeTol(brep):
eTol = 0
for edge in brep.Edges:
if edge.Tolerance > eTol: eTol=edge.Tolerance
return eTol
def MaxVerTol(brep):
vTol = 0
for v in brep.Vertices:
if v.Tolerance > vTol: vTol=v.Tolerance
return vTol
def RetrimSrf():
tol = sc.doc.ModelAbsoluteTolerance
id = rs.GetObject("Select a surface to retrim.", 8, preselect=True, select=True)
if not id: return
brep = sc.doc.Objects.Find(id).Geometry
if isinstance( brep,Rhino.Geometry.Extrusion): brep = brep.ToBrep()
tolStr = None
outTol= False
if not brep.IsValid:
eTol = MaxEdgeTol(brep)
#vTol = MaxVerTol(brep)
tolStr = " Object is not valid."
outTol= False
if eTol >= tol:
tolStr = tolStr + " Edge tolerances = " + str(round(eTol, 6)) + " This is larger then the file tolerance."
outTol=True
# if vTol >= tol:
# tolStr = tolStr + "Vertex tolerances = " + str(vTol)
# outTol=True
bb = brep.GetBoundingBox(True)
#sc.doc.Objects.AddBrep(bb.ToBrep())
trims = brep.Trims
crvs = brep.DuplicateEdgeCurves()
face = brep.Faces[0]
srf = face.UnderlyingSurface()
brep2 = srf.ToBrep()
face2 = brep2.Faces[0]
brep2 = face2.Split(crvs, tol)
#sc.doc.Objects.AddBrep(brep2)
newBrep=None
#brep2.Faces.ShrinkFaces()
for face in brep2.Faces:
temp = face.DuplicateFace(False)
tempBB = temp.GetBoundingBox(True)
#sc.doc.Objects.AddBrep(tempBB.ToBrep())
if BBCompare(tempBB, bb):
newBrep = face.DuplicateFace(False)
break
failStr = "Failed to retrim the surface."
if outTol:
failStr = failStr + tolStr
if newBrep is not None:
sc.doc.Objects.Replace(id, newBrep)
print "The surface was successfully retrimmed."
return
print failStr
pass
if __name__ == "__main__":
RetrimSrf()
)
replace that by:
RetrimSrf()
so without the check if the function is called as main function
depends on what’s wrong with them
It’s the same problem like above which can be fixed per the script from Pascal. Only it’s not so easy to explode the polysurface, start the script and look for the critical surface. Or would the script be to slow for a polysurface, if all surfaces would be retrimmed?
Attached an example polysurface.
InvisibleSurfaceOfPolysurface.3dm (938.6 KB)
if I run _ExtractBadSrf I get a lot of flagged ones:
So I think it is worthwhile to see if you can ask your customer to try different exporting options and see if that gives you better surfaces.
Also I noticed that your file has a very rough tolerance setting of 0.1mm, is this your setting or the result of opening the file you got from your customer in Rhino? In what program was the file made?
You can use this after extracting the bad surfaces, so that you can apply the script on multiple surfaces at once:
import Rhino
import scriptcontext as sc
import rhinoscriptsyntax as rs
def BBCompare(BB1,BB2):
#BB2 = original
tol = sc.doc.ModelAbsoluteTolerance
x = BB1.Min.DistanceTo(BB2.Min)
#rs.AddPoints([BB1.Min,BB2.Min])
y = BB1.Max.DistanceTo(BB2.Max)
if BB1.Min.DistanceTo(BB2.Min)< tol:
if BB1.Max.DistanceTo(BB2.Max)< tol:
#print "BBTrue"
return True
return False
def MaxEdgeTol(brep):
eTol = 0
for edge in brep.Edges:
if edge.Tolerance > eTol: eTol=edge.Tolerance
return eTol
def MaxVerTol(brep):
vTol = 0
for v in brep.Vertices:
if v.Tolerance > vTol: vTol=v.Tolerance
return vTol
def RetrimSrf():
tol = sc.doc.ModelAbsoluteTolerance
ids = rs.GetObjects("Select surfaces to retrim.", 8, preselect=True, select=True)
if not ids: return
for id in ids:
brep = sc.doc.Objects.Find(id).Geometry
if isinstance( brep,Rhino.Geometry.Extrusion): brep = brep.ToBrep()
tolStr = None
outTol= False
if not brep.IsValid:
eTol = MaxEdgeTol(brep)
#vTol = MaxVerTol(brep)
tolStr = " Object is not valid."
outTol= False
if eTol >= tol:
tolStr = tolStr + " Edge tolerances = " + str(round(eTol, 6)) + " This is larger then the file tolerance."
outTol=True
# if vTol >= tol:
# tolStr = tolStr + "Vertex tolerances = " + str(vTol)
# outTol=True
bb = brep.GetBoundingBox(True)
#sc.doc.Objects.AddBrep(bb.ToBrep())
trims = brep.Trims
crvs = brep.DuplicateEdgeCurves()
face = brep.Faces[0]
srf = face.UnderlyingSurface()
brep2 = srf.ToBrep()
face2 = brep2.Faces[0]
brep2 = face2.Split(crvs, tol)
#sc.doc.Objects.AddBrep(brep2)
newBrep=None
#brep2.Faces.ShrinkFaces()
for face in brep2.Faces:
temp = face.DuplicateFace(False)
tempBB = temp.GetBoundingBox(True)
#sc.doc.Objects.AddBrep(tempBB.ToBrep())
if BBCompare(tempBB, bb):
newBrep = face.DuplicateFace(False)
continue
failStr = "Failed to retrim the surface."
if outTol:
failStr = failStr + tolStr
if newBrep is not None:
sc.doc.Objects.Replace(id, newBrep)
print "The surface was successfully retrimmed."
continue
print failStr
pass
RetrimSrf()
Thank you very much Gijs, the script is a big helper now. 
Also thank you for the background info so I can try to get better models in the future. My client isn’t creating the model, he got the model by his client, so I don’t have a direct contact to the model creator. But your information are very detailed and I hope to get them to them to the source creator.
Have a nice day,
Micha