Section annotation option not to draw full line between the markers

Here's the example - https://i.imgur.com/db09OVF.png

To make it work need to add BBIM_Section property set to the annotation and set "HasConnectedSectionLine" to False (by default it's True).
Also added preview for this feature in viewport.

src/blenderbim/blenderbim/bim/data/pset/Psets_BBIM_Annotation.ifc

@@ -1,7 +1,7 @@
 ISO-10303-21;
 HEADER;
 FILE_DESCRIPTION((),'2;1');
-FILE_NAME('EPset_Annotation.ifc','2020-01-01T00:00:00',(),(),'EPset_Annotation','EPset_Annotation',$);
+FILE_NAME('Psets_BBIM_Annotation.ifc','2020-01-01T00:00:00',(),(),'Psets_BBIM_Annotation','Psets_BBIM_Annotation',$);
 FILE_SCHEMA(('IFC4'));
 ENDSEC;
 DATA;
@@ -12,5 +12,11 @@ DATA;
 #5=IFCPROPERTYSETTEMPLATE('0iKwujnQL9IevVQato8f7Z',$,'BBIM_Batting','',.PSET_OCCURRENCEDRIVEN.,'IfcAnnotation',(#6,#7));
 #6=IFCSIMPLEPROPERTYTEMPLATE('0t2LEesGT1QRQtrIZUAR8L',$,'Thickness','Batting thickness',.P_SINGLEVALUE.,'IfcPositiveLengthMeasure',$,$,$,$,$,.READWRITE.);
 #7=IFCSIMPLEPROPERTYTEMPLATE('082PndS6v2kBOiJoSboMnh',$,'Reverse pattern direction','Reverse batting pattern (swap starting and ending points)',.P_SINGLEVALUE.,'IfcBoolean',$,$,$,$,$,.READWRITE.);
+#8=IFCPROPERTYSETTEMPLATE('1Dx2EiZnP67xotInXpwz90',$,'BBIM_Section','',.PSET_OCCURRENCEDRIVEN.,'IfcAnnotation',(#9,#10,#11,#12,#13));
+#9=IFCSIMPLEPROPERTYTEMPLATE('2a_9s8spHDc9dZHtgg71XL',$,'ShowStartArrow','Display start arrow.',.P_SINGLEVALUE.,'IfcBoolean',$,$,$,$,$,.READWRITE.);
+#10=IFCSIMPLEPROPERTYTEMPLATE('3i6SH_GbT7zhKea$wVE56A',$,'StartArrowSymbol','Custom symbol for the start of the section marker arrow.',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
+#11=IFCSIMPLEPROPERTYTEMPLATE('1DtsPn5a9FG8$zXHDDMavY',$,'ShowEndArrow','Display end arrow.',.P_SINGLEVALUE.,'IfcBoolean',$,$,$,$,$,.READWRITE.);
+#12=IFCSIMPLEPROPERTYTEMPLATE('2$6U0mLI9AiPRWeBabdY3u',$,'EndArrowSymbol','Custom symbol for the end of the section marker arrow',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
+#13=IFCSIMPLEPROPERTYTEMPLATE('1naFqntIL7igCY7hCaE7kq',$,'HasConnectedSectionLine','Connect or disconnect section markers with line (by default = True).',.P_SINGLEVALUE.,'IfcBoolean',$,$,$,$,$,.READWRITE.);
 ENDSEC;
 END-ISO-10303-21;

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

@@ -140,4 +140,24 @@ class DecoratorData:
             thickness = thickness * unit_scale if thickness else 1.5
             cls.data[obj.name] = thickness
             return thickness
-        return 1.5
+
+    @classmethod
+    def get_section_pset_data(cls, obj):
+        result = cls.data.get(obj.name, None)
+        if result is not None:
+            return result
+        element = tool.Ifc.get_entity(obj)
+        if element:
+            # default values
+            pset_data = {
+                "HasConnectedSectionLine": True,
+                "ShowStartArrow": True,
+                "StartArrowSymbol": "",
+                "ShowEndArrow": True,
+                "EndArrowSymbol": "",
+            }
+            obj_pset_data = ifcopenshell.util.element.get_pset(element, "BBIM_Section") or {}
+            pset_data.update(obj_pset_data)
+
+            cls.data[obj.name] = pset_data
+            return pset_data

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

@@ -309,6 +309,7 @@ class BaseDecorator:
         indices = []
         idx = 0
 
+        # TODO: are we adding same verts twice?
         for edge in mesh.edges:
             vertices.extend(edge.verts)
             indices.append((idx, idx + 1))
@@ -1818,6 +1819,7 @@ class SectionDecorator(LevelDecorator):
     GEOM_GLSL = """
     uniform vec2 winsize;
     uniform float viewportDrawingScale;
+    uniform float connect_markers;
 
     layout(lines) in;
     layout(line_strip, max_vertices=MAX_POINTS) out;
@@ -1879,14 +1881,7 @@ class SectionDecorator(LevelDecorator):
         EmitVertex();
         EndPrimitive();
 
-        // start reference divider
+
-        p = p0w + normalize(vec4(-1, 0, 0, 0)) * viewportDrawingScale * CIRCLE_SIZE;
-        gl_Position = WIN2CLIP(p);
-        EmitVertex();
-        p = p0w + normalize(vec4(1, 0, 0, 0)) * viewportDrawingScale * CIRCLE_SIZE;
-        gl_Position = WIN2CLIP(p);
-        EmitVertex();
-        EndPrimitive();
 
         // end edge circle
         for(int i=0; i<CIRCLE_SEGS; i++) {
@@ -1918,23 +1913,41 @@ class SectionDecorator(LevelDecorator):
         EmitVertex();
         EndPrimitive();
 
+        float divider_line_size;
+        if (connect_markers > 0) {
+            divider_line_size = CIRCLE_SIZE;
+        } else {
+            divider_line_size = CIRCLE_SIZE * 3;
+        }
+
+        // start reference divider
+        p = p0w + normalize(vec4(-1, 0, 0, 0)) * viewportDrawingScale * divider_line_size;
+        gl_Position = WIN2CLIP(p);
+        EmitVertex();
+        p = p0w + normalize(vec4(1, 0, 0, 0)) * viewportDrawingScale * CIRCLE_SIZE;
+        gl_Position = WIN2CLIP(p);
+        EmitVertex();
+        EndPrimitive();
+
         // end reference divider
         p = p1w + normalize(vec4(-1, 0, 0, 0)) * viewportDrawingScale * CIRCLE_SIZE;
         gl_Position = WIN2CLIP(p);
         EmitVertex();
-        p = p1w + normalize(vec4(1, 0, 0, 0)) * viewportDrawingScale * CIRCLE_SIZE;
+        p = p1w + normalize(vec4(1, 0, 0, 0)) * viewportDrawingScale * divider_line_size;
         gl_Position = WIN2CLIP(p);
         EmitVertex();
         EndPrimitive();
 
         // stem
-        p = p0w + gap;
+        if (connect_markers > 0) {
-        gl_Position = WIN2CLIP(p);
+            p = p0w + gap;
-        EmitVertex();
+            gl_Position = WIN2CLIP(p);
-        p = p1w - gap;
+            EmitVertex();
-        gl_Position = WIN2CLIP(p);
+            p = p1w - gap;
-        EmitVertex();
+            gl_Position = WIN2CLIP(p);
-        EndPrimitive();
+            EmitVertex();
+            EndPrimitive();
+        }
     }
     """
 
@@ -1945,7 +1958,11 @@ class SectionDecorator(LevelDecorator):
             verts, idxs = self.get_mesh_geom(obj)
         vert_map = {v.freeze(): (obj.matrix_world.inverted() @ v).x for v in verts}
         verts = sorted(verts, key=lambda v: vert_map[v], reverse=True)
-        self.draw_lines(context, obj, verts, idxs)
+        # TODO: add dashed line to shader
+        # mind the vertices limit
+        section_pset_data = DecoratorData.get_section_pset_data(obj)
+        connect_markers = section_pset_data["HasConnectedSectionLine"]
+        self.draw_lines(context, obj, verts, idxs, extra_float_kwargs={"connect_markers": float(connect_markers)})
 
 
 class TextDecorator(BaseDecorator):

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

@@ -31,10 +31,12 @@ import ifcopenshell.util.representation
 import blenderbim.tool as tool
 import blenderbim.bim.module.drawing.helper as helper
 import blenderbim.bim.module.drawing.annotation as annotation
-from math import pi, ceil, atan, degrees
+
-from mathutils import Vector
+from blenderbim.bim.module.drawing.data import DecoratorData
-from mathutils import geometry
 from blenderbim.bim.ifc import IfcStore
+
+from math import pi, ceil, atan, degrees
+from mathutils import geometry, Vector
 from bpy_extras import view3d_utils
 
 
@@ -367,13 +369,25 @@ class SvgWriter:
             self.draw_edge_annotation(obj, classes)
 
     def draw_edge_annotation(self, obj, classes):
-        predefined_type = classes[2]
+        predefined_type = classes[2].split("-", 1)[1]
 
-        if predefined_type.endswith("-BATTING"):
+        x_offset = self.raw_width / 2
-            x_offset = self.raw_width / 2
+        y_offset = self.raw_height / 2
-            y_offset = self.raw_height / 2
+        matrix_world = obj.matrix_world
-            matrix_world = obj.matrix_world
 
+        def draw_simple_edge_annotation(v0, v1):
+            v0_global = matrix_world @ obj.data.vertices[v0].co.xyz
+            v1_global = matrix_world @ obj.data.vertices[v1].co.xyz
+            v0 = self.project_point_onto_camera(v0_global)
+            v1 = self.project_point_onto_camera(v1_global)
+            start = Vector(((x_offset + v0.x), (y_offset - v0.y)))
+            end = Vector(((x_offset + v1.x), (y_offset - v1.y)))
+            line = self.svg.add(
+                self.svg.line(start=start * self.svg_scale, end=end * self.svg_scale, class_=" ".join(classes))
+            )
+
+        # BATTING ANNOTATIONS
+        if predefined_type == "BATTING":
             v0_global = matrix_world @ obj.data.vertices[0].co.xyz
             v1_global = matrix_world @ obj.data.vertices[1].co.xyz
             v0 = self.project_point_onto_camera(v0_global)
@@ -439,23 +453,43 @@ class SvgWriter:
             )
             self.svg.add(self.svg.polyline(points=points, class_=" ".join(classes), style=polyline_style))
 
-        else:
+        elif predefined_type == "SECTION":
-            x_offset = self.raw_width / 2
+            section_pset_data = DecoratorData.get_section_pset_data(obj)
-            y_offset = self.raw_height / 2
+            connect_markers = section_pset_data["HasConnectedSectionLine"]
-            matrix_world = obj.matrix_world
+            if connect_markers:
-            for edge in obj.data.edges:
+                for edge in obj.data.edges:
-                v0_global = matrix_world @ obj.data.vertices[edge.vertices[0]].co.xyz
+                    draw_simple_edge_annotation(*edge.vertices[:])
-                v1_global = matrix_world @ obj.data.vertices[edge.vertices[1]].co.xyz
+            else:
-                v0 = self.project_point_onto_camera(v0_global)
+                for edge in obj.data.edges:
-                v1 = self.project_point_onto_camera(v1_global)
+                    v0_global = matrix_world @ obj.data.vertices[edge.vertices[0]].co.xyz
-                start = Vector(((x_offset + v0.x), (y_offset - v0.y)))
+                    v1_global = matrix_world @ obj.data.vertices[edge.vertices[1]].co.xyz
-                end = Vector(((x_offset + v1.x), (y_offset - v1.y)))
+                    v0 = self.project_point_onto_camera(v0_global)
-                vector = end - start
+                    v1 = self.project_point_onto_camera(v1_global)
-                line = self.svg.add(
+                    start = Vector(((x_offset + v0.x), (y_offset - v0.y)))
-                    self.svg.line(
+                    end = Vector(((x_offset + v1.x), (y_offset - v1.y)))
-                        start=tuple(start * self.svg_scale), end=tuple(end * self.svg_scale), class_=" ".join(classes)
+
+                    edge_dir = (end - start).normalized()
+                    circle_radius = 5
+                    segment_size = circle_radius * 3
+
+                    self.svg.add(
+                        self.svg.line(
+                            start=start * self.svg_scale,
+                            end=start * self.svg_scale + edge_dir * segment_size,
+                            class_=" ".join(classes),
+                        )
                     )
-                )
+                    self.svg.add(
+                        self.svg.line(
+                            start=end * self.svg_scale,
+                            end=end * self.svg_scale - edge_dir * segment_size,
+                            class_=" ".join(classes),
+                        )
+                    )
+
+        else:
+            for edge in obj.data.edges:
+                draw_simple_edge_annotation(*edge.vertices[:])
 
     def draw_leader_annotation(self, obj):
         self.draw_line_annotation(obj)