Problem with importing modules pythonocc

[JP Mertens]

Hi I can't imort Utils from OCC

Traceback (most recent call last):
File "C:/Users/Jan Philipp Mertens/PycharmProjects/untitled/Cross section.py", line 4, in <module>
import OCC.Utils
ImportError: No module named 'OCC.Utils'</module>

was it maybe renamed?

Thanks in advance

[Thomas Krijnen]

Hi,

Are you by any chance referring to the code you found in this article [1]? I made a comment [2] there as well about the changes in newer PythonOCC versions. The article is from 2015 and has not since been updated. I think that particular OCC.Utils.Topo can now be found here [3]. Overall the required changes should be minimal. If you get things working, it would be very much appreciated if you leave some instructions there in a comment for future users.

Kind regards,
Thomas

[1] http://academy.ifcopenshell.org/using-ifcopenshell-and-pythonocc-to-generate-cross-sections-directly-from-an-ifc-file/
[2] http://academy.ifcopenshell.org/using-ifcopenshell-and-pythonocc-to-generate-cross-sections-directly-from-an-ifc-file/#comment-57
[3] https://github.com/tpaviot/pythonocc-core/blob/master/src/Extend/TopologyUtils.py

[JP Mertens]

Hi Thomas,

Thank you for the quick responce. Indeed your workaround from [2] helped it not crashing anymore. However the viewer now freezes up without crashing when I run the programm. I tried the ideas from Wouter Coebergh but I can't seem to import topods.

I will leave a comment once I get it working.

Best,
JP

[Thomas Krijnen]

I think there are known issues running the PythonOCC viewer module from PyCharm. Try running from the command line directly.

Kind regards,
Thomas

[JP Mertens]

Hi Thomas,
I came back to work on it again.

I wrote this

for product, shape in product_shapes:
section_edges = OCC.BRepAlgoAPI.BRepAlgoAPI_Section(section_face, shape).Shape()

exp = OCC.TopExp.TopExp_Explorer(section_face, OCC.TopAbs.TopAbs_EDGE)
while exp.More():
section_edges = OCC.TopoDS.topods.Edge(exp.Current())
exp.Next()

if len(section_edges) > 0:
edges = OCC.TopTools.TopTools_HSequenceOfShape()
edges_handle = OCC.TopTools.Handle_TopTools_HSequenceOfShape(edges)

wires = OCC.TopTools.TopTools_HSequenceOfShape()
wires_handle = OCC.TopTools.Handle_TopTools_HSequenceOfShape(wires)
###

as a workaround for section_edges = list(OCC.Utils.Topo(section).edges())
However it says object of type TopoDS_Edge has no length. Any idea what I am doing wrong here? Thanks again in advance

Best regards

JP

[Thomas Krijnen]

section_edges = OCC.BRepAlgoAPI.BRepAlgoAPI_Section(section_face, shape).Shape()

I think that should be section_face and set section_edges = [] to an empty list.

Then you can do section_edges.append(OCC.TopoDS.topods.Edge(exp.Current())), because now you're overwriting the edge.

I think then it would work.

[JP Mertens]

Hi Thomas,

Thank you for your quick reply and sorry for continuing to ask, since I am very new to this.

I now have:

for product, shape in product_shapes:
    section = OCC.BRepAlgoAPI.BRepAlgoAPI_Section(section_face, shape).Shape()

section_edges = []

exp = OCC.TopExp.TopExp_Explorer(section, OCC.TopAbs.TopAbs_EDGE)

while exp.More():
    section_edges = OCC.TopoDS.topods.Edge(exp.Current())
    exp.Next()

section_edges.append(OCC.TopoDS.topods.Edge(exp.Current()))

if len(section_edges) > 0:
    edges = OCC.TopTools.TopTools_HSequenceOfShape()
    edges_handle = OCC.TopTools.Handle_TopTools_HSequenceOfShape(edges)

    wires = OCC.TopTools.TopTools_HSequenceOfShape()
    wires_handle = OCC.TopTools.Handle_TopTools_HSequenceOfShape(wires)

however i get: section_edges.append(OCC.TopoDS.topods.Edge(exp.Current()))
AttributeError: 'TopoDS_Edge' object has no attribute 'append'

Did I insert the line at the right place, or is it supposed to go in the while loop? I get the same exception when I incert in the loop aswell. section_edges.append(OCC.TopoDS.topods.Edge(exp.Current()))

Thanks again!

[Thomas Krijnen]

You're still overwriting section_edges with a single edge.

I meant to replace section_edges = OCC.TopoDS.topods.Edge(exp.Current()) with section_edges.append(OCC.TopoDS.topods.Edge(exp.Current()))

[JP Mertens]

Hi Thomas,

Thanks for the help. In the end after some other changes I got it working with:

for product, shape in product_shapes:
print(product)

section = OCC.BRepAlgoAPI.BRepAlgoAPI_Section(section_face, shape).Shape()

exp = OCC.TopExp.TopExp_Explorer(section, OCC.TopAbs.TopAbs_EDGE)
section_edges = []
while exp.More():
    edge = OCC.TopoDS.topods.Edge(exp.Current())
    exp.Next()
    section_edges.append(edge)

[Thomas Krijnen]

Yep, looks good to me. Can you also post that to the academy website? Thanks.

[Hamid Kiavarz]

Hi,

What is the equal syntax for the below statements:
topo = OCC.Utils.Topo(shape)
for face in topo.faces():
surf = OCC.BRep.BRep_Tool.Surface(face)

    I need to extract the faces of a wall

    Thanks,
    Hamid