You can now add arbitrary annotation to a drawing, not just belonging to one of the preset types

src/ifcblenderexport/blenderbim/bim/operator.py

@@ -2152,7 +2152,16 @@ class CutSection(bpy.types.Operator):
         ifc_cutter.section_level_obj = None
         ifc_cutter.grid_objs = []
         ifc_cutter.text_objs = []
+        ifc_cutter.misc_objs = []
         for obj in camera.users_collection[0].objects:
+            if 'IfcGrid' in obj.name:
+                ifc_cutter.grid_objs.append(obj)
+            elif 'IfcGroup' in obj.name and obj.type == 'CAMERA':
+                ifc_cutter.camera_obj = obj
+
+            if 'IfcAnnotation/' not in obj.name:
+                continue
+
             if 'Leader' in obj.name:
                 ifc_cutter.leader_obj = (obj, obj.data)
             elif 'Stair' in obj.name:
@@ -2167,16 +2176,14 @@ class CutSection(bpy.types.Operator):
                 ifc_cutter.hidden_objs.append((obj, obj.data))
             elif 'Solid' in obj.name:
                 ifc_cutter.solid_objs.append((obj, obj.data))
-            elif 'IfcGrid' in obj.name:
-                ifc_cutter.grid_objs.append(obj)
             elif 'Plan Level' in obj.name:
                 ifc_cutter.plan_level_obj = obj
             elif 'Section Level' in obj.name:
                 ifc_cutter.section_level_obj = obj
-            elif obj.type == 'CAMERA':
-                ifc_cutter.camera_obj = obj
             elif obj.type == 'FONT':
                 ifc_cutter.text_objs.append(obj)
+            else:
+                ifc_cutter.misc_objs.append(obj)
 
         ifc_cutter.section_box = {
             'projection': tuple(projection),

src/ifcblenderexport/blenderbim/bim/svgwriter.py

@@ -159,6 +159,9 @@ class SvgWriter():
 
         self.draw_ifc_annotation()
 
+        for obj in self.ifc_cutter.misc_objs:
+            self.draw_misc_annotation(obj, ['IfcAnnotation'])
+
         for obj_data in self.ifc_cutter.hidden_objs:
             self.draw_line_annotation(obj_data, ['hidden'])
 
@@ -264,6 +267,25 @@ class SvgWriter():
                 line = self.svg.add(self.svg.line(start=tuple(start * self.scale),
                     end=tuple(end * self.scale), class_=' '.join(annotation['classes'])))
 
+    def draw_misc_annotation(self, obj, classes):
+        # We have to decide whether this should come from Blender or from IFC.
+        # For the moment, for convenience of experimenting with ideas, it comes
+        # from Blender. In the future, it should probably come from IFC.
+        classes.extend(self.get_attribute_classes(obj))
+        if len(obj.data.polygons) == 0:
+            self.draw_edge_annotation(obj, classes)
+            return
+        x_offset = self.raw_width / 2
+        y_offset = self.raw_height / 2
+        matrix_world = obj.matrix_world
+        for polygon in obj.data.polygons:
+            points = [obj.data.vertices[v] for v in polygon.vertices]
+            projected_points = [self.project_point_onto_camera(matrix_world @ p.co.xyz) for p in points]
+            d = ' '.join(['L {} {}'.format(
+                (x_offset + p.x) * self.scale, (y_offset - p.y) * self.scale)
+                for p in projected_points])
+            d = 'M{}'.format(d[1:])
+            path = self.svg.add(self.svg.path(d=d, class_=' '.join(classes)))
     def draw_line_annotation(self, obj_data, classes):
         # TODO: properly scope these offsets
         x_offset = self.raw_width / 2