Improved meshbuilder's mesh handling

src/rod/builder/primitives.py

@@ -1,4 +1,5 @@
 import dataclasses
+import os
 import pathlib
 
 import trimesh
@@ -64,6 +65,7 @@ def _geometry(self) -> rod.Geometry:
 class MeshBuilder(PrimitiveBuilder):
     mesh_path: str | pathlib.Path
     scale: NDArray
+    is_empty: bool = False
 
     def __post_init__(self) -> None:
         """
@@ -74,20 +76,12 @@ def __post_init__(self) -> None:
             AssertionError: If the scale is not a 3D vector.
             TypeError: If the mesh_path is not a str or pathlib.Path.
         """
+        mesh_path = pathlib.Path(self.mesh_path)
+        if not mesh_path.is_file():
+            raise FileNotFoundError(f"Mesh file not found at {self.mesh_path}")
 
-        if isinstance(self.mesh_path, str):
-            extension = pathlib.Path(self.mesh_path).suffix
-        elif isinstance(self.mesh_path, pathlib.Path):
-            extension = self.mesh_path.suffix
-        else:
-            raise TypeError(
-                f"Expected str or pathlib.Path for mesh_path, got {type(self.mesh_path)}"
-            )
-
-        self.mesh: trimesh.base.Trimesh = trimesh.load(
-            str(self.mesh_path),
-            force="mesh",
-            file_type=extension,
+        self.mesh: trimesh.base.Trimesh = trimesh.load_mesh(
+            file_obj=mesh_path,
         )
 
         assert self.scale.shape == (

tests/test_meshbuilder.py

@@ -74,3 +74,17 @@ def test_builder_creation_custom_mesh():
     ), f"{builder.mesh.moment_inertia} != {mesh.moment_inertia}"
 
     assert builder.mesh.volume == mesh.volume, f"{builder.mesh.volume} != {mesh.volume}"
+
+
+def test_builder_empty_mesh():
+    with tempfile.TemporaryDirectory() as tmp:
+        with tempfile.NamedTemporaryFile(suffix=".stl", dir=tmp, delete=False) as fp:
+
+            builder = MeshBuilder(
+                name="test_mesh",
+                mesh_path=fp.name,
+                mass=1.0,
+                scale=np.array([1.0, 1.0, 1.0]),
+            )
+
+    assert builder.is_empty == True, f"builder.is_empty is {builder.is_empty} != True"