Added support for defining parts using STL format (#42)

.gitattributes

@@ -1,2 +1,3 @@
 *.step binary
 *.png binary
+*.stl binary

README.md

@@ -166,7 +166,20 @@ parts:
 Store the model in "bold.step"
 </td>
 <td><img src="https://github.com/openvmp/partcad/blob/main/examples/part_step/bolt.png?raw=true"></td>
+</tr>
 <tr>
+<td><a href="https://en.wikipedia.org/wiki/STL_(file_format)">STL</a></td>
+<td>
+<code># partcad.yaml
+parts:
+    cube:
+        type: stl</code>
+
+<br/>
+Store the model in "cube.stl"
+</td>
+<td><img src="https://github.com/openvmp/partcad/blob/main/examples/part_stl/cube.png?raw=true"></td>
+</tr>
 <tr>
 <td><a href="https://github.com/CadQuery/cadquery">CadQuery</a></td>
 <td>
@@ -179,7 +192,7 @@ parts:
 Place the CadQuery script in "cube.py"
 </td>
 <td><img src="https://github.com/openvmp/partcad/blob/main/examples/part_cadquery_primitive/cube.png?raw=true"></td>
-<tr>
+</tr>
 https://github.com/openvmp/partcad/blob/main/examples/assembly_logo/logo.png?raw=true
 <tr>
 <td><a href="https://github.com/gumyr/build123d">build123d</a></td>
@@ -193,7 +206,7 @@ parts:
 Place the build123d script in "cube.py"
 </td>
 <td><img src="https://github.com/openvmp/partcad/blob/main/examples/part_cadquery_primitive/cube.png?raw=true"></td>
-<tr>
+</tr>
 </table>
 
 Other methods to define parts are coming in soon (e.g. SCAD).

examples/part_step/partcad.yaml

@@ -1,9 +1,8 @@
 desc: PartCAD example project to demonstrate parts implemented using STEP files
 parts:
   bolt:
-    desc: A sample bolt
+    desc: M8x30-screw
     type: step
-    description: M8x30-screw
 render:
   png:
     prefix: ./

examples/part_stl/partcad.yaml

@@ -0,0 +1,11 @@
+desc: PartCAD example project to demonstrate parts implemented using STL files
+parts:
+  cube:
+    desc: A cube defined in STL
+    type: stl
+render:
+  png:
+    prefix: ./
+    width: 128
+    height: 128
+  markdown: README.md

src/partcad/part_factory_stl.py

@@ -0,0 +1,23 @@
+#
+# OpenVMP, 2024
+#
+# Author: Roman Kuzmenko
+# Created: 2024-01-06
+#
+# Licensed under Apache License, Version 2.0.
+#
+
+import build123d as b3d
+from . import part_factory as pf
+from . import part as p
+
+
+class PartFactoryStl(pf.PartFactory):
+    def __init__(self, ctx, project, part_config):
+        super().__init__(ctx, project, part_config, extension=".stl")
+        # Complement the config object here if necessary
+        self._create(part_config)
+
+    def instantiate(self, part):
+        shape = b3d.Mesher().read(part.path)[0].wrapped
+        part.set_shape(shape)

src/partcad/project.py

@@ -11,6 +11,7 @@
 
 from . import project_config
 from . import part_factory_step as pfs
+from . import part_factory_stl as pfstl
 from . import part_factory_cadquery as pfc
 from . import part_factory_build123d as pfb
 from . import assembly_factory_assy as afa
@@ -88,6 +89,9 @@ def init_parts(self):
             elif part_config["type"] == "step":
                 logging.info("Initializing STEP part: %s..." % part_name)
                 pfs.PartFactoryStep(self.ctx, self, part_config)
+            elif part_config["type"] == "stl":
+                logging.info("Initializing STL part: %s..." % part_name)
+                pfstl.PartFactoryStl(self.ctx, self, part_config)
             else:
                 logging.error(
                     "Invalid part type encountered: %s: %s" % (part_name, part_config)

tests/unit/test_part.py

@@ -24,23 +24,31 @@
 }
 
 
-def test_part_get_1():
-    """Load part from a project by the part name"""
+def test_part_get_step_1():
+    """Load a STEP part from a project by the part name"""
     ctx = pc.Context("examples/part_step")
     repo1 = ctx.get_project("this")
     bolt = repo1.get_part("bolt")
     assert bolt is not None
     assert bolt.get_wrapped() is not None
 
 
-def test_part_get_2():
-    """Load part from the context by the project and part names"""
+def test_part_get_step_2():
+    """Load a STEP part from the context by the project and part names"""
     ctx = pc.Context("examples/part_step")
     bolt = ctx.get_part("bolt", "this")
     assert bolt is not None
     assert bolt.get_wrapped() is not None
 
 
+def test_part_get_stl():
+    """Load a STL part"""
+    ctx = pc.Context("examples/part_stl")
+    part = ctx.get_part("cube", "this")
+    assert part is not None
+    assert part.get_wrapped() is not None
+
+
 def test_part_get_3():
     """Instantiate a project by a local import config and load a part"""
     ctx = pc.Context()  # Empty config