Merge pull request #32 from Rich43/codex/enforce-stl-printability-checks

Enforce printability validation for STL export

parametric_cad/export/stl.py

@@ -5,13 +5,16 @@ import numpy as np
 from pathlib import Path
 from datetime import datetime
 
+from parametric_cad.printability import PrintabilityValidator
+
 class STLExporter:
     """Export trimesh objects to STL with optional previews."""
 
-    def __init__(self, output_dir="output", binary=False):
+    def __init__(self, output_dir: str = "output", binary: bool = False) -> None:
         self.output_dir = output_dir
         self.binary = binary
         os.makedirs(self.output_dir, exist_ok=True)
+        self.validator = PrintabilityValidator()
 
     def _ensure_mesh(self, obj):
         if isinstance(obj, tm.Trimesh):
@@ -35,6 +38,12 @@ class STLExporter:
             else:
                 combined = combined.convex_hull
 
+        errors = self.validator.validate_mesh(combined)
+        if errors:
+            raise ValueError(
+                "Printability validation failed: " + ", ".join(errors)
+            )
+
         filename = f"{base_filename}.stl"
         if timestamp:
             ts = datetime.now().strftime("%Y%m%d_%H%M%S")

tests/test_export.py

@@ -1,8 +1,8 @@
 import os
 from pathlib import Path
+import pytest
 from parametric_cad.primitives.box import Box
 from parametric_cad.primitives.cylinder import Cylinder
-from parametric_cad.primitives.sphere import Sphere
 from parametric_cad.export.stl import STLExporter
 
 EXPECTED_DIR = Path(__file__).parent / "expected_stl"
@@ -23,10 +23,10 @@ def test_stl_exporter(tmp_path):
 
 def test_ascii_stl_multiple_objects(tmp_path):
     exporter = STLExporter(output_dir=tmp_path)
-    box = Box(1.0, 2.0, 1.0)
-    cyl = Cylinder(radius=0.5, height=1.0)
-    sph = Sphere(radius=0.25)
-    path = exporter.export_meshes([box, cyl, sph], "combo", preview=False)
+    box = Box(1.0, 2.0, 1.0).at(0, 0, 0.5)
+    cyl = Cylinder(radius=2.0, height=1.0, sections=8).at(3, 0, 0.5)
+    box2 = Box(0.5, 0.5, 0.5).at(0, 3, 0.25)
+    path = exporter.export_meshes([box, cyl, box2], "combo", preview=False)
     assert os.path.isfile(path)
     assert path == str(tmp_path / "combo.stl")
     with open(path, "r", encoding="utf-8") as f:
@@ -34,3 +34,10 @@ def test_ascii_stl_multiple_objects(tmp_path):
     with open(EXPECTED_DIR / "combo.stl", "r", encoding="utf-8") as f:
         expected = f.read()
     assert contents == expected
+
+
+def test_exporter_printability_failure(tmp_path):
+    exporter = STLExporter(output_dir=tmp_path)
+    big_box = Box(300.0, 10.0, 10.0)
+    with pytest.raises(ValueError):
+        exporter.export_mesh(big_box, "bad_box", preview=False)