Adding Fillet/Round Causing Python to Crash

[ardarslan]

Hello,

Thanks a lot for the amazing work! I'm currently using the following repository: https://gitlab.com/qub_femg/machine-learning/mfcad2-dataset/-/blob/main/README.md?ref_type=heads

Is there anyone who is using the same repository and found a solution for fillet/round addition causing Python to crash? (This happens at the following line: https://gitlab.com/qub_femg/machine-learning/mfcad2-dataset/-/blob/main/Features/round.py#L53. There is no error thrown, this issue is also mentioned in the README file here: https://gitlab.com/qub_femg/machine-learning/mfcad2-dataset/-/blob/main/README.md?ref_type=heads)

I opened the issue here as well because the owner of mfcad2-dataset stated that this issue is related to pythonocc, and the line that causes Python to crash is related to this repository.

Best,
Arda

[tpaviot]

@ardarslan this repo relies on a pretty outdated version of pythonocc (7.5.1). Did you try with latest release 7.7.2 ?

[tnakaicode]

Please rewrite round.py as follows and run main.py to try it out.

Just before generating Fillet, the program outputs the previous shapes, Edges and Faces in a STEP file.
This is done because Debugger and Try & Exception cannot avoid the phenomenon that the entire main function stops.
Perhaps it is a fatal bug in executing MakeFillet and the radius that is set is too small, or there is a problem with the shape of the Face that defines the Fillet.
Let's look at some real-life examples and see if we can guess the cause of the problem.

import random

from OCC.Core.BRepFilletAPI import BRepFilletAPI_MakeFillet
from OCC.Core.GProp import GProp_GProps
from OCC.Core._BRepGProp import brepgprop_SurfaceProperties
from OCC.Core.Message import Message_ProgressRange, Message_Report, Message_PrinterToReport
from OCC.Core.BRep import BRep_Builder
from OCC.Core.TopoDS import TopoDS_Compound
from OCC.Extend.DataExchange import write_step_file

import OCCUtils.Topology
import OCCUtils.face
import Utils.shape_factory as shape_factory
import Utils.parameters as param
from Features.machining_features import MachiningFeature

import OCCUtils.edge


def ask_surface_area(f):
    props = GProp_GProps()

    brepgprop_SurfaceProperties(f, props)
    area = props.Mass()
    return area

def export_step(shp, edge, radius, max_radius):
    stepfile = "round.step"
    textfile = "round.txt"
    
    builder = BRep_Builder()
    compound = TopoDS_Compound()
    builder.MakeCompound(compound)
    builder.Add(compound, shp)
    builder.Add(compound, edge)
    write_step_file(compound, stepfile)
    
    fp = open(textfile, "w")
    fp.write(f"{radius:.5f}\n")
    fp.write(f"{max_radius:.5f}\n")
    fp.close()

class Round(MachiningFeature):
    def __init__(self, shape, label_map, min_len, clearance, feat_names, edges):
        super().__init__(shape, label_map, min_len, clearance, feat_names)
        self.shifter_type = None
        self.bound_type = None
        self.depth_type = None
        self.feat_type = "round"
        self.edges = edges

    def add_feature(self):
        fillet_maker = BRepFilletAPI_MakeFillet(self.shape)
        new_edges = []

        for edge in self.edges:
            e_util = OCCUtils.edge.Edge(edge)
            if e_util.length() >= self.min_len:
                new_edges.append(edge)

        self.edges = new_edges

        while len(self.edges) > 0:
            edge = random.choice(self.edges)
            e_util = OCCUtils.edge.Edge(edge)
            max_radius = e_util.length() / 10

            if max_radius > param.round_radius_max:
                max_radius = param.round_radius_max

            radius = random.uniform(param.round_radius_min, max_radius)
            print(e_util.length(), radius)
            export_step(self.shape, edge, radius, max_radius)

            try:
                fillet_maker.Add(radius, edge)
                fillet_maker.Build()
                shape = fillet_maker.Shape()
                self.edges.remove(edge)
                break

            except:
                self.edges.remove(edge)
                continue
        print()
        

        try:
            fmap = shape_factory.map_face_before_and_after_feat(self.shape, fillet_maker)
            label_map = shape_factory.map_from_shape_and_name(fmap, self.label_map,
                                                                   shape, self.feat_names.index(self.feat_type))

            return shape, label_map, self.edges

        except:
            return self.shape, self.label_map, self.edges

OCC was old (5.5.0), so there were some fixes, but I don't have a GitLab account that delays Pull Requests, so you're on your own to fix it.