Release: Mesh.contains fix (#2535)

`mesh.contains` with multiple hits wasn't tested, and the embree 2 -> 4
move introduced a bug.

- test and fix #2534
- restores the scale-aware offset for multiple hits.

Author: mikedh

pyproject.toml

@@ -5,7 +5,7 @@ requires = ["setuptools >= 61.0", "wheel"]
 [project]
 name = "trimesh"
 requires-python = ">=3.8"
-version = "4.12.1"
+version = "4.12.2"
 authors = [{name = "Michael Dawson-Haggerty", email = "mikedh@kerfed.com"}]
 license = {file = "LICENSE.md"}
 description = "Import, export, process, analyze and view triangular meshes."

tests/test_ray.py

@@ -113,6 +113,25 @@ def test_contains():
         assert test_centroid.all()
 
 
+def test_contains_cavity():
+    # https://github.com/mikedh/trimesh/issues/2534
+    from trimesh import ray as ray_mod
+
+    mesh = g.trimesh.boolean.difference(
+        [
+            g.trimesh.creation.box(extents=[1, 1, 1]),
+            g.trimesh.creation.box(extents=[0.1, 0.1, 0.1]),
+        ]
+    )
+    engines = [ray_mod.ray_triangle.RayMeshIntersector]
+    if ray_mod.has_embree:
+        engines.append(ray_mod.ray_pyembree.RayMeshIntersector)
+    for engine in engines:
+        mesh.ray = engine(mesh)
+        # origin sits inside the subtracted cavity
+        assert not mesh.contains([[0, 0, 0]])[0]
+
+
 def test_on_vertex():
     for use_embree in [False]:
         m = g.trimesh.creation.box(use_embree=use_embree)
@@ -135,7 +154,7 @@ def test_on_edge():
     for use_embree in [True, False]:
         m = g.get_mesh("7_8ths_cube.stl", use_embree=use_embree)
 
-        points = [[4.5, 0, -23], [4.5, 0, -2], [0, -1e-6, 0.0], [0, 0, -1]]
+        points = [[4.5, 0, -23], [4.5, 0, -2], [0, -1e-4, 0.0], [0, 0, -1]]
         truth = [False, True, True, True]
         result = g.trimesh.ray.ray_util.contains_points(m.ray, points)
 

trimesh/ray/ray_pyembree.py

@@ -17,11 +17,9 @@
 # embree operates on float32 values
 _embree_dtype = np.float32
 
-# when calculating multiple hits we offset the hit to
-# advance the ray past the plane of the triangle we hit
-# hardcode offset for rays larger than our resolution:
-#   np.finfo(_embree_dtype).resolution * 10
-_ray_offset = 1e-5
+# scale-aware base ray offset to step past hit triangles above f32 ULP
+_ray_offset_factor = 1e-6
+_ray_offset_floor = 1e-8
 
 
 class RayMeshIntersector:
@@ -150,7 +148,8 @@ def intersects_id(
 
         if multiple_hits or return_locations:
             # how much to offset ray to transport to the other side of face
-            ray_offsets = ray_directions * _ray_offset
+            base_offset = max(_ray_offset_floor, self.mesh.scale * _ray_offset_factor)
+            ray_offsets = ray_directions * base_offset
 
             # grab the planes from triangles
             plane_origins = self.mesh.triangles[:, 0, :]
@@ -214,7 +213,7 @@ def intersects_id(
 
             # clean hits step onto the new face with a fresh base offset
             ray_origins[ok_rays] = new_origins + ray_offsets[ok_rays]
-            ray_offsets[ok_rays] = ray_directions[ok_rays] * _ray_offset
+            ray_offsets[ok_rays] = ray_directions[ok_rays] * base_offset
             # stuck rays double their offset and step further to try to clear
             ray_offsets[dupe_rays] *= 2.0
             ray_origins[dupe_rays] += ray_offsets[dupe_rays]

trimesh/ray/ray_util.py

@@ -54,10 +54,11 @@ def contains_points(
         )
 
     # cast a ray both forwards and backwards
+    # need multiple_hits=True so the parity test counts cavity walls
     _location, index_ray, _c = intersector.intersects_location(
         np.vstack((points[inside_aabb], points[inside_aabb])),
         np.vstack((ray_directions, -ray_directions)),
-        multiple_hits=False,
+        multiple_hits=True,
     )
 
     # if we hit nothing in either direction just return with no hits