USD Converter: Added skipping when material does not exist

Author: ft-lab

tests/data/simple_box_no_material.urdf

@@ -0,0 +1,10 @@
+<?xml verison="1.0"?>
+<robot name="simple_box_no_material">
+  <link name="link1">
+    <visual>
+      <geometry>
+        <box size="2.0 2.0 2.0"/>
+      </geometry>
+    </visual>
+  </link>
+</robot>

tests/test_parser.py

@@ -222,6 +222,14 @@ def test_load_error_duplicate_transmission_names(self):
         with self.assertRaisesRegex(RuntimeError, r".*transmission: Transmission name 'transmission_1' already exists \(line: 8\).*"):
             parser.parse()
 
+    def test_has_no_material(self):
+        # Load the specified URDF file.
+        model_path = pathlib.Path("tests/data/simple_box_no_material.urdf")
+        parser = URDFParser(model_path)
+
+        materials = parser.get_materials()
+        self.assertEqual(len(materials), 0)
+
     def test_get_basic_information(self):
         # Get basic information about a URDF.
 

urdf_usd_converter/_impl/material.py

@@ -8,6 +8,11 @@
 
 
 def convert_materials(data: ConversionData):
-    # TODO: Implement
+    materials = data.urdf_parser.get_materials()
+    if not len(materials):
+        return
+
     data.libraries[Tokens.Materials] = usdex.core.addAssetLibrary(data.content[Tokens.Contents], Tokens.Materials, format="usdc")
     data.references[Tokens.Materials] = {}
+
+    # TODO: Implement