Rewrite of is_closed non check exact check.

stl/base.py

@@ -1,5 +1,6 @@
 import enum
 import math
+import itertools
 import numpy
 import logging
 try: # pragma: no cover
@@ -346,21 +347,64 @@ def update_areas(self, normals=None):
  def update_centroids(self):
  self.centroids = numpy.mean([self.v0, self.v1, self.v2], axis=0)
 
- def check(self):
- '''Check the mesh is valid or not'''
- return self.is_closed()
+ def check(self, exact=False):
+ """Check the mesh is valid or not
+
+ :param bool exact: Perform exact checks.
+ """
+ return self.is_closed(exact=exact)
+
+ def is_closed(self, exact=False): # pragma: no cover
+ """Check the mesh is closed or not
+
+ :param bool exact: Perform a exact check on edges.
+ """
+
+ if not exact:
+ self.warning(
+ """
+ Use of not exact is_closed check. This check can lead to misleading
+ results. You could try to use `exact=True`.
+ See: https://github.com/wolph/numpy-stl/issues/198
+ """.strip()
+ )
+ normals = numpy.asarray(self.normals, dtype=numpy.float64)
+ allowed_max_errors = (
+ numpy.abs(normals).sum(axis=0) * numpy.finfo(numpy.float32).eps
+ )
+ if (numpy.abs(normals.sum(axis=0)) <= allowed_max_errors).all():
+ return True
 
- def is_closed(self): # pragma: no cover
- """Check the mesh is closed or not"""
- if numpy.isclose(self.normals.sum(axis=0), 0, atol=1e-4).all():
- return True
  else:
- self.warning('''
- Your mesh is not closed, the mass methods will not function
- correctly on this mesh. For more info:
- https://github.com/WoLpH/numpy-stl/issues/69
- '''.strip())
- return False
+ reversed_triangles = (
+ numpy.cross(self.v1 - self.v0, self.v2 - self.v0) * self.normals
+ ).sum(axis=1) < 0
+ directed_edges = set(
+ tuple(edge.ravel() if not rev else edge[::-1, :].ravel())
+ for rev, edge in zip(
+ itertools.cycle(reversed_triangles),
+ itertools.chain(
+ self.vectors[:, (0, 1), :],
+ self.vectors[:, (1, 2), :],
+ self.vectors[:, (2, 0), :],
+ ),
+ )
+ )
+ if len(directed_edges) == 3 * self.data.size:
+ undirected_edges = set(
+ frozenset((edge[:3], edge[3:])) for edge in directed_edges
+ )
+ if len(directed_edges) == 2 * len(undirected_edges):
+ return True
+
+ self.warning(
+ """
+ Your mesh is not closed, the mass methods will not function
+ correctly on this mesh. For more info:
+ https://github.com/WoLpH/numpy-stl/issues/69
+ """.strip()
+ )
+ return False
 
  def get_mass_properties(self):
  '''