From f4f650fa98e9d6007ce661be9ee8d1c676136e40 Mon Sep 17 00:00:00 2001
From: Cass <aftersending1@gmail.com>
Date: Wed, 29 Jul 2026 21:59:32 -0400
Subject: [PATCH] Give PoissonRecon a writable temp directory

---
 opendm/mesh.py     |  5 +++++
 tests/test_mesh.py | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 tests/test_mesh.py

diff --git a/opendm/mesh.py b/opendm/mesh.py
index 584458bfb..bb6200b97 100644
--- a/opendm/mesh.py
+++ b/opendm/mesh.py
@@ -136,6 +136,9 @@ def dem_to_mesh_gridded(inGeotiff, outMesh, maxVertexCount, maxConcurrency=1):
 def screened_poisson_reconstruction(inPointCloud, outMesh, depth = 8, samples = 1, maxVertexCount=100000, pointWeight=4, threads=context.num_cores):
 
     mesh_path, mesh_filename = os.path.split(outMesh)
+    # PoissonRecon otherwise writes out-of-core PR_* files to the caller's
+    # working directory, which may be read-only even when mesh_path is writable.
+    tempdir = os.path.abspath(mesh_path or '.')
     # mesh_path = path/to
     # mesh_filename = odm_mesh.ply
 
@@ -157,6 +160,7 @@ def screened_poisson_reconstruction(inPointCloud, outMesh, depth = 8, samples =
             'bin': context.poisson_recon_path,
             'outfile': outMeshDirty,
             'infile': inPointCloud,
+            'tempdir': tempdir,
             'depth': depth,
             'samples': samples,
             'pointWeight': pointWeight,
@@ -167,6 +171,7 @@ def screened_poisson_reconstruction(inPointCloud, outMesh, depth = 8, samples =
         try:
             system.run('"{bin}" --in "{infile}" '
                     '--out "{outfile}" '
+                    '--tempDir "{tempdir}" '
                     '--depth {depth} '
                     '--pointWeight {pointWeight} '
                     '--samplesPerNode {samples} '
diff --git a/tests/test_mesh.py b/tests/test_mesh.py
new file mode 100644
index 000000000..04901e4c8
--- /dev/null
+++ b/tests/test_mesh.py
@@ -0,0 +1,47 @@
+import os
+import tempfile
+import unittest
+from unittest.mock import patch
+
+from opendm import mesh
+
+
+class TestMesh(unittest.TestCase):
+    def test_poisson_uses_output_directory_for_temporary_files(self):
+        with tempfile.TemporaryDirectory() as root:
+            mesh_dir = os.path.join(root, "mesh output")
+            os.mkdir(mesh_dir)
+            point_cloud = os.path.join(root, "cloud.ply")
+            output = os.path.join(mesh_dir, "odm_mesh.ply")
+            dirty = os.path.join(mesh_dir, "odm_mesh.dirty.ply")
+            commands = []
+
+            def run(command):
+                commands.append(command)
+                if "--linearFit" in command:
+                    with open(dirty, "wb"):
+                        pass
+
+            with patch.object(mesh.system, "run", side_effect=run):
+                with patch.object(
+                    mesh.context, "poisson_recon_path", "PoissonRecon"
+                ):
+                    with patch.object(
+                        mesh.context,
+                        "omvs_reconstructmesh_path",
+                        "ReconstructMesh",
+                    ):
+                        result = mesh.screened_poisson_reconstruction(
+                            point_cloud, output, threads=3
+                        )
+
+            self.assertEqual(result, output)
+            self.assertEqual(len(commands), 2)
+            self.assertIn(
+                '--tempDir "{}"'.format(os.path.abspath(mesh_dir)),
+                commands[0],
+            )
+
+
+if __name__ == "__main__":
+    unittest.main()