Add shared abstraction for STEP assembly

.github/workflows/main.yml

@@ -24,6 +24,7 @@ jobs:
         run: mypy --strict
           common.py
           entities/*.py
+          cadquery_helpers.py
           dfn_configs.py
           generate*.py
           test_entities.py

cadquery_helpers.py

@@ -0,0 +1,26 @@
+import cadquery as cq
+from OCP.Message import Message, Message_Gravity  # type: ignore
+
+
+class StepAssembly:
+    """
+    A STEP assembly.
+    """
+    def __init__(self, name: str):
+        self.assembly = cq.Assembly(name=name)
+
+        # Less verbose output
+        for printer in Message.DefaultMessenger_s().Printers():
+            printer.SetTraceLevel(Message_Gravity.Message_Fail)
+
+    def add_body(self, body: cq.Workplane, name: str, color: cq.Color):
+        """
+        Add a body to the assembly.
+        """
+        self.assembly.add(body, name=name, color=color)
+
+    def save(self, path: str):
+        """
+        Write the STEP file to the specified path.
+        """
+        self.assembly.save(path, 'STEP', mode='fused', write_pcurves=False)

generate_chip.py

@@ -606,6 +606,7 @@ def generate_3d(
     config: ChipConfig,
 ) -> None:
     import cadquery as cq
+    from cadquery_helpers import StepAssembly
 
     print(f'Generating pkg 3D model "{full_name}": {uuid_3d}')
 
@@ -633,22 +634,17 @@ def generate_3d(
         .translate(translation) \
         .translate((edge_offset + edge / 2, 0, 0))
 
-    assembly = cq.Assembly(name=full_name) \
-        .add(inner, name="inner", color=cq.Color("gray16")) \
-        .add(left, name="left", color=cq.Color("gainsboro")) \
-        .add(right, name="right", color=cq.Color("gainsboro"))
+    assembly = StepAssembly(full_name)
+    assembly.add_body(inner, 'inner', cq.Color("gray16"))
+    assembly.add_body(left, 'left', cq.Color("gainsboro"))
+    assembly.add_body(right, 'right', cq.Color("gainsboro"))
 
     dir_path = path.join('out', library, 'pkg', uuid_pkg)
     if not (path.exists(dir_path) and path.isdir(dir_path)):
         makedirs(dir_path)
     filename = f'{uuid_3d}.step'
 
-    # Less verbose output
-    from OCP.Message import Message, Message_Gravity  # type: ignore
-    for printer in Message.DefaultMessenger_s().Printers():
-        printer.SetTraceLevel(Message_Gravity.Message_Fail)
-
-    assembly.save(path.join(dir_path, filename), 'STEP', mode='fused', write_pcurves=False)
+    assembly.save(path.join(dir_path, filename))
 
 
 def generate_dev(