allow specification of dxf layer names to import. for issue #1051

cadquery/occ_impl/importers/__init__.py

@@ -67,15 +67,19 @@ def importStep(fileName):
     return cq.Workplane("XY").newObject(solids)
 
 
-def importDXF(filename, tol=1e-6, exclude=[]):
+def importDXF(filename, tol=1e-6, exclude=[], include=[]):
     """
-    Loads a DXF file into a cadquery Workplane.
+    Loads a DXF file into a Workplane.
+
+    All layers are imported by default.  Provide a layer include or exclude list
+     to select layers.  Layer names are handled as case-insensitive.
 
     :param fileName: The path and name of the DXF file to be imported
-    :param tol: The tolerance used for merging edges into wires (default: 1e-6)
-    :param exclude: a list of layer names not to import (default: [])
+    :param tol: The tolerance used for merging edges into wires
+    :param exclude: a list of layer names not to import
+    :param include: a list of layer names to import
     """
 
-    faces = _importDXF(filename, tol, exclude)
+    faces = _importDXF(filename, tol, exclude, include)
 
     return cq.Workplane("XY").newObject(faces)

cadquery/occ_impl/importers/dxf.py

@@ -157,24 +157,42 @@ def _dxf_convert(elements, tol):
     return rv
 
 
-def _importDXF(filename: str, tol: float = 1e-6, exclude: List[str] = []) -> List[Face]:
+def _importDXF(
+    filename: str, tol: float = 1e-6, exclude: List[str] = [], include: List[str] = [],
+) -> List[Face]:
     """
     Loads a DXF file into a list of faces.
 
     :param fileName: The path and name of the DXF file to be imported
-    :param tol: The tolerance used for merging edges into wires (default: 1e-6)
-    :param exclude: a list of layer names not to import (default: [])
+    :param tol: The tolerance used for merging edges into wires
+    :param exclude: a list of layer names not to import
+    :param include: a list of layer names to import
     """
 
-    # normalize layer names to conform the DXF spec
-    exclude_lwr = [ex.lower() for ex in exclude]
+    if exclude and include:
+        raise ValueError("you may specify either 'include' or 'exclude' but not both")
 
     dxf = ezdxf.readfile(filename)
     faces = []
 
-    for name, layer in dxf.modelspace().groupby(dxfattrib="layer").items():
-        res = _dxf_convert(layer, tol) if name.lower() not in exclude_lwr else None
-        if res:
+    layers = dxf.modelspace().groupby(dxfattrib="layer")
+
+    # normalize layer names to conform the DXF spec
+    names = set([name.lower() for name in layers.keys()])
+
+    if include:
+        selected = names & set([name.lower() for name in include])
+    elif exclude:
+        selected = names - set([name.lower() for name in exclude])
+    else:
+        selected = names
+
+    if not selected:
+        raise ValueError("no DXF layers selected")
+
+    for name, layer in layers.items():
+        if name.lower() in selected:
+            res = _dxf_convert(layers[name], tol)
             wire_sets = sortWiresByBuildOrder(res)
             for wire_set in wire_sets:
                 faces.append(Face.makeFromWires(wire_set[0], wire_set[1:]))

cadquery/sketch.py

@@ -170,6 +170,7 @@ def importDXF(
         filename: str,
         tol: float = 1e-6,
         exclude: List[str] = [],
+        include: List[str] = [],
         angle: Real = 0,
         mode: Modes = "a",
         tag: Optional[str] = None,
@@ -178,7 +179,7 @@ def importDXF(
         Import a DXF file and construct face(s)
         """
 
-        res = Compound.makeCompound(_importDXF(filename, tol, exclude))
+        res = Compound.makeCompound(_importDXF(filename, tol, exclude, include))
 
         return self.face(res, angle, mode, tag)
 

tests/test_importers.py

@@ -7,6 +7,7 @@
 
 from cadquery import importers, Workplane
 from tests import BaseTest
+from pytest import approx, raises
 
 # where unit test output will be saved
 OUTDIR = tempfile.gettempdir()
@@ -138,6 +139,26 @@ def testImportDXF(self):
         self.assertEqual(obj.faces().size(), 2)
         self.assertEqual(obj.wires().size(), 2)
 
+        obj = importers.importDXF(filename, include=["Layer2"])
+        assert obj.vertices("<XY").val().toTuple() == approx(
+            (104.2871791623584, 0.0038725018551133, 0.0)
+        )
+
+        obj = importers.importDXF(filename, include=["Layer2", "Layer3"])
+        assert obj.vertices("<XY").val().toTuple() == approx(
+            (104.2871791623584, 0.0038725018551133, 0.0)
+        )
+        assert obj.vertices(">XY").val().toTuple() == approx(
+            (257.6544359816229, 93.62447646419444, 0.0)
+        )
+
+        with raises(ValueError):
+            importers.importDXF(filename, include=["Layer1"], exclude=["Layer3"])
+
+        with raises(ValueError):
+            # Layer4 does not exist
+            importers.importDXF(filename, include=["Layer4"])
+
         # test dxf extrusion into the third dimension
         extrusion_value = 15.0
         tmp = obj.wires()

tests/test_sketch.py

@@ -717,3 +717,11 @@ def test_dxf_import():
     s3 = Sketch().circle(20).importDXF(filename, tol=1e-3, mode="s")
 
     assert s3._faces.isValid()
+
+    s4 = Sketch().importDXF(filename, tol=1e-3, include=["0"])
+
+    assert s4._faces.isValid()
+
+    s5 = Sketch().importDXF(filename, tol=1e-3, exclude=["1"])
+
+    assert s5._faces.isValid()