type check for threshold

pyproject.toml

@@ -5,7 +5,7 @@ requires = ["setuptools >= 61.0", "wheel"]
 [project]
 name = "trimesh"
 requires-python = ">=3.8"
-version = "4.5.2"
+version = "4.5.3"
 authors = [{name = "Michael Dawson-Haggerty", email = "mikedh@kerfed.com"}]
 license = {file = "LICENSE.md"}
 description = "Import, export, process, analyze and view triangular meshes."

tests/test_voxel.py

@@ -67,16 +67,29 @@ def test_marching(self):
             g.log.warning("no skimage, skipping marching cubes test")
             return
 
+        march = g.trimesh.voxel.ops.matrix_to_marching_cubes
+
         # make sure offset is correct
         matrix = g.np.ones((3, 3, 3), dtype=bool)
-        mesh = g.trimesh.voxel.ops.matrix_to_marching_cubes(matrix=matrix)
+        mesh = march(matrix=matrix)
         assert mesh.is_watertight
 
-        mesh = g.trimesh.voxel.ops.matrix_to_marching_cubes(matrix=matrix).apply_scale(
-            3.0
-        )
+        mesh = march(matrix=matrix).apply_scale(3.0)
         assert mesh.is_watertight
 
+        # try an array full of a small number
+        matrix = g.np.full((3, 3, 3), 0.01, dtype=g.np.float64)
+        # set some to zero
+        matrix[:2, :2, :2] = 0.0
+
+        a = march(matrix)
+        assert a.is_watertight
+
+        # but above the threshold it should be not empty
+        b = march(matrix, threshold=-0.001)
+        assert b.is_watertight
+        assert b.volume > a.volume
+
     def test_marching_points(self):
         """
         Try marching cubes on points

trimesh/util.py

@@ -25,7 +25,7 @@
 from .iteration import chain
 
 # use our wrapped types for wider version compatibility
-from .typed import Union
+from .typed import Dict, List, Optional, Set, Union
 
 # create a default logger
 log = logging.getLogger("trimesh")
@@ -2359,7 +2359,9 @@ def is_ccw(points, return_all=False):
     return ccw, area, centroid
 
 
-def unique_name(start, contains, counts=None):
+def unique_name(
+    start: str, contains: Union[Dict, Set, List], counts: Optional[Dict] = None
+):
     """
     Deterministically generate a unique name not
     contained in a dict, set or other grouping with

trimesh/voxel/ops.py

@@ -2,6 +2,7 @@
 
 from .. import util
 from ..constants import log
+from ..typed import ArrayLike, Floating, Number, Optional
 
 
 def fill_orthographic(dense):
@@ -95,7 +96,9 @@ def fill_base(sparse_indices):
 fill_voxelization = fill_base
 
 
-def matrix_to_marching_cubes(matrix, pitch=1.0, threshold=None):
+def matrix_to_marching_cubes(
+    matrix: ArrayLike, pitch: Floating = 1.0, threshold: Optional[Number] = None
+):
     """
     Convert an (n, m, p) matrix into a mesh, using marching_cubes.
 
@@ -106,7 +109,8 @@ def matrix_to_marching_cubes(matrix, pitch=1.0, threshold=None):
     pitch : float or length-3 tuple of floats, optional
       Voxel spacing in each dimension
     threshold : float or None, optional
-      If specified, converts the input 'matrix' into a Boolean matrix by setting values above to 'threshold' to True and those below or equal to False
+      If specified, converts the input into a boolean
+      matrix by considering values above `threshold` as True
 
 
     Returns
@@ -119,9 +123,8 @@ def matrix_to_marching_cubes(matrix, pitch=1.0, threshold=None):
 
     from ..base import Trimesh
 
-    if isinstance(threshold, float) or isinstance(threshold, int) :
-        matrix_as_array = np.asarray(matrix)
-        matrix = np.where(matrix_as_array > threshold, True, False)
+    if threshold is not None:
+        matrix = np.asanyarray(matrix) > threshold
     else:
         matrix = np.asanyarray(matrix, dtype=bool)