experimental svg to dxf conversion for drawings

Example - https://imgur.com/a/AkvLlbZ

src/blenderbim/Makefile

@@ -363,6 +363,8 @@ endif
 	cd dist/working && . env/bin/activate && $(PIP) install pytest --target=./site-packages
 	# Provides Brickschema functionality
 	cd dist/working && . env/bin/activate && $(PIP) install "brickschema[persistence]==0.7.6a2" --target=./site-packages
+	# Required for SVG to DXF conversion
+	cd dist/working && . env/bin/activate && $(PIP) install "ezxdf" --target=./site-packages
 	cp -r dist/working/site-packages/* dist/blenderbim/libs/site/packages/
 	rm -rf dist/working
 

src/blenderbim/blenderbim/bim/module/drawing/__init__.py

@@ -41,6 +41,7 @@ classes = (
     operator.CleanWireframes,
     operator.ContractSheet,
     operator.ContractTargetView,
+    operator.ConvertSVGToDXF,
     operator.CreateDrawing,
     operator.CreateSheets,
     operator.DisableAddAnnotationType,

src/blenderbim/blenderbim/bim/module/drawing/operator.py

@@ -44,7 +44,7 @@ import blenderbim.bim.module.drawing.helper as helper
 import blenderbim.bim.export_ifc
 from blenderbim.bim.module.drawing.decoration import CutDecorator
 from blenderbim.bim.module.drawing.data import DecoratorData, DrawingsData
-from typing import NamedTuple, List
+from typing import NamedTuple, List, Union
 from lxml import etree
 from mathutils import Vector, Color, Matrix
 from timeit import default_timer as timer
@@ -2685,3 +2685,50 @@ class AddReferenceImage(bpy.types.Operator, Operator):
         )
         tool.Style.reload_material_from_ifc(material)
         tool.Geometry.record_object_materials(obj)
+
+
+class ConvertSVGToDXF(bpy.types.Operator):
+    bl_idname = "bim.convert_svg_to_dxf"
+    bl_label = "Convert SVG to DXF"
+    bl_options = {"REGISTER", "UNDO"}
+    view: bpy.props.StringProperty()
+    bl_description = "Convert current drawing's .svg to .dxf.\n\nSHIFT+CLICK to convert all selected drawings"
+    convert_all: bpy.props.BoolProperty(name="Convert All", default=False, options={"SKIP_SAVE"})
+
+    def invoke(self, context, event):
+        # convert all drawings on shift+click
+        # make sure to use SKIP_SAVE on property, otherwise it might get stuck
+        if event.type == "LEFTMOUSE" and event.shift:
+            self.open_all = True
+        return self.execute(context)
+
+    def execute(self, context):
+        if self.convert_all:
+            drawings = [
+                tool.Ifc.get().by_id(d.ifc_definition_id) for d in context.scene.DocProperties.drawings if d.is_selected
+            ]
+        else:
+            drawings = [tool.Ifc.get().by_id(context.scene.DocProperties.drawings.get(self.view).ifc_definition_id)]
+
+        drawing_uris: list[Path] = []
+        drawings_not_found: list[str] = []
+
+        for drawing in drawings:
+            drawing_uri = tool.Drawing.get_document_uri(tool.Drawing.get_drawing_document(drawing))
+            if drawing_uri is None or not os.path.exists(drawing_uri):
+                drawings_not_found.append(drawing.Name)
+            else:
+                drawing_uris.append(Path(drawing_uri))
+
+        if drawings_not_found:
+            msg = "Some drawings .svg files were not found, need to print them first: \n{}.".format(
+                "\n".join(drawings_not_found)
+            )
+            self.report({"ERROR"}, msg)
+            return {"CANCELLED"}
+
+        for drawing_uri in drawing_uris:
+            tool.Drawing.convert_svg_to_dxf(drawing_uri, drawing_uri.with_suffix(".dxf"))
+
+        self.report({"INFO"}, f"{len(drawing_uris)} drawings were converted to .dxf.")
+        return {"FINISHED"}

src/blenderbim/blenderbim/bim/module/drawing/ui.py

@@ -268,6 +268,11 @@ class BIM_PT_drawings(Panel):
                 col = row.column()
                 col.alignment = "RIGHT"
 
+                convert_to_dxf = row.row(align=True)
+                op = convert_to_dxf.operator("bim.convert_svg_to_dxf", text="", icon="IMAGE_DATA")
+                op.view = active_drawing.name
+                convert_to_dxf.enabled = active_drawing.ifc_definition_id > 0
+
                 op = row.operator("bim.select_all_drawings", icon="SELECT_SUBTRACT", text="")
 
                 open_drawing_button = row.row(align=True)

src/blenderbim/blenderbim/tool/drawing.py

@@ -27,7 +27,6 @@ import shutil
 import logging
 import shapely
 import platform
-from shapely.ops import unary_union
 import mathutils
 import subprocess
 import numpy as np
@@ -43,6 +42,7 @@ import blenderbim.bim.module.drawing.sheeter as sheeter
 import blenderbim.bim.module.drawing.scheduler as scheduler
 import blenderbim.bim.module.drawing.annotation as annotation
 import blenderbim.bim.module.drawing.helper as helper
+from shapely.ops import unary_union
 from blenderbim.bim.module.drawing.data import FONT_SIZES, DecoratorData
 from blenderbim.bim.module.drawing.prop import get_diagram_scales, BOX_ALIGNMENT_POSITIONS, ANNOTATION_TYPES_DATA
 from lxml import etree
@@ -50,6 +50,7 @@ from mathutils import Vector, Matrix
 from fractions import Fraction
 import collections
 from typing import Optional, Union
+from pathlib import Path
 
 
 class Drawing(blenderbim.core.tool.Drawing):
@@ -385,7 +386,9 @@ class Drawing(blenderbim.core.tool.Drawing):
         return ifcopenshell.util.representation.get_context(tool.Ifc.get(), "Model", "Body", "MODEL_VIEW")
 
     @classmethod
-    def get_document_uri(cls, document, description=None):
+    def get_document_uri(
+        cls, document: ifcopenshell.entity_instance, description: Optional[str] = None
+    ) -> Union[str, None]:
         if getattr(document, "Location", None):
             if os.path.isabs(document.Location):
                 return document.Location
@@ -430,7 +433,7 @@ class Drawing(blenderbim.core.tool.Drawing):
                 return rel.RelatingGroup
 
     @classmethod
-    def get_drawing_document(cls, drawing):
+    def get_drawing_document(cls, drawing: ifcopenshell.entity_instance) -> ifcopenshell.entity_instance:
         for rel in drawing.HasAssociations:
             if rel.is_a("IfcRelAssociatesDocument"):
                 return rel.RelatingDocument
@@ -1103,7 +1106,6 @@ class Drawing(blenderbim.core.tool.Drawing):
         reference_element: ifcopenshell.entity_instance,
         context: ifcopenshell.entity_instance,
     ) -> ifcopenshell.entity_instance:
-
         if reference_element.is_a("IfcGridAxis"):
             return cls.generate_grid_axis_reference_annotation(drawing, reference_element, context)
 
@@ -1991,3 +1993,60 @@ class Drawing(blenderbim.core.tool.Drawing):
             rotate180z = mathutils.Matrix.Rotation(math.radians(180.0), 4, "Z")
             return mathutils.Matrix.Translation(location) @ rotation.to_matrix().to_4x4() @ rotate180z
         return mathutils.Matrix.Translation(location) @ rotation.to_matrix().to_4x4()
+
+    @classmethod
+    def convert_svg_to_dxf(cls, svg_filepath: Path, dxf_filepath: Path) -> None:
+        import ezdxf
+        import xml.etree.ElementTree as ET
+
+        SVG = "{http://www.w3.org/2000/svg}"
+        IFC = "{http://www.ifcopenshell.org/ns}"
+
+        doc = ezdxf.new("R2010")
+        msp = doc.modelspace()
+        svg = ET.parse(svg_filepath).getroot()
+
+        def finalize_dxf():
+            doc.saveas(dxf_filepath)
+
+        drawing = svg.findall(f"{SVG}g[@{IFC}name]")
+        if not drawing:
+            finalize_dxf()
+            return
+        drawing = drawing[0]
+
+        NUMBER = r"-?\d+\.?\d+"
+        COORD = rf"{NUMBER},{NUMBER}"
+        POLYLINE_PATTERN = rf"M{COORD} (?:L{COORD} ?)+Z? ?"
+        MULTI_POLYLINE_PATTERN = rf"^({POLYLINE_PATTERN})+$"
+
+        for element_g in drawing.findall(f"{SVG}g"):
+            paths = element_g.findall(f"{SVG}path")
+
+            for path in paths:
+                path = path.attrib["d"]
+
+                if not re.match(MULTI_POLYLINE_PATTERN, path):
+                    # print(f'Path "{path}" doesn\'t match expected pattern {MULTI_POLYLINE_PATTERN}')
+                    continue
+
+                for polyline_path in re.findall(POLYLINE_PATTERN, path):
+                    points = re.findall(rf"{NUMBER}", polyline_path)
+                    points = [float(p) for p in points]
+                    POINT_SIZE = 2
+
+                    grouped_points = []
+                    for i in range(0, len(points), POINT_SIZE):
+                        point = points[i : i + POINT_SIZE]
+                        point[1] *= -1
+                        grouped_points.append(point)
+                    points = grouped_points
+
+                    # Z marks closed polylines
+                    is_closed_polyline = polyline_path.rstrip().endswith("Z")
+                    if is_closed_polyline or len(points) > 2:
+                        msp.add_lwpolyline(points, close=is_closed_polyline)
+                    else:  # LINE
+                        msp.add_line(*points)
+
+        finalize_dxf()