add the choice to not import all dxf layers (#442)

* add the choice to not import all dxf layers

this is especially useful for ignoring layers in drawings containing note text or dimensions

* remove a blank line

* Rework layer exclusion in dxf import

* add dxf for layer tests

* add tests for dxf import layer filtering and extrusion

fix edges/wires mixup

remove extra `)`

fix var name typo

fix lint

Co-authored-by: Adam Urbańczyk <adam-urbanczyk@users.noreply.github.com>

Author: greyltc

cadquery/occ_impl/importers.py

@@ -214,19 +214,20 @@ def _dxf_convert(elements, tol):
     return rv
 
 
-def importDXF(filename, tol=1e-6):
+def importDXF(filename, tol=1e-6, exclude=[]):
     """
     Loads a DXF file into a cadquery Workplane.
     
     :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: [])
     """
 
     dxf = ezdxf.readfile(filename)
     faces = []
 
     for name, layer in dxf.modelspace().groupby(dxfattrib="layer").items():
-        res = _dxf_convert(layer, tol)
+        res = _dxf_convert(layer, tol) if name not in exclude else None
         if res:
             wire_sets = sortWiresByBuildOrder(res)
             for wire_set in wire_sets:

tests/test_importers.py

@@ -130,6 +130,20 @@ def testImportDXF(self):
         self.assertTrue(obj.val().isValid())
         self.assertEqual(obj.faces().size(), 1)
 
+        # test layer filtering
+        filename = os.path.join(testdataDir, "three_layers.dxf")
+        obj = importers.importDXF(filename, exclude=["Layer2"])
+        self.assertTrue(obj.val().isValid())
+        self.assertEqual(obj.faces().size(), 2)
+        self.assertEqual(obj.wires().size(), 2)
+
+        # test dxf extrusion into the third dimension
+        extrusion_value = 15.0
+        tmp = obj.wires()
+        tmp.ctx.pendingWires = tmp.vals()
+        threed = tmp.extrude(extrusion_value)
+        self.assertEqual(threed.findSolid().BoundingBox().zlen, extrusion_value)
+
 
 if __name__ == "__main__":
     import unittest