Skeleton of "add fitting" operator which decides appropriate fitting type

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

@@ -31,6 +31,7 @@ from . import (
     stair,
     window,
     opening,
+    mep,
     pie,
     workspace,
     profile,
@@ -105,6 +106,7 @@ classes = (
     space.GenerateSpace,
     space.GenerateSpacesFromWalls,
     space.ToggleSpaceVisibility,
+    mep.FitFlowSegments,
     prop.BIMModelProperties,
     prop.BIMArrayProperties,
     prop.BIMStairProperties,

src/blenderbim/blenderbim/bim/module/model/mep.py

@@ -39,7 +39,92 @@ V = lambda *x: Vector([float(i) for i in x])
 float_is_zero = lambda f: 0.0001 >= f >= -0.0001
 
 
-class MEPGenerator:
+class FitFlowSegments(bpy.types.Operator, tool.Ifc.Operator):
+    bl_idname = "bim.fit_flow_segments"
+    bl_label = "Fit Flow Segments"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def _execute(self, context):
+        selected_objs = []
+        selected_profiles = []
+
+        selected_class = None
+        for obj in context.selected_objects:
+            element = tool.Ifc.get_entity(obj)
+            if element and element.is_a("IfcFlowSegment"):
+                if selected_class and not element.is_a(selected_class):
+                    return  # The user is mixing up ducts and pipes.
+                profile = tool.Model.get_flow_segment_profile(element)
+                if profile:
+                    selected_profiles.append(profile)
+                    selected_objs.append(obj)
+                    selected_class = element.is_a()
+
+        total_selected_objs = len(selected_objs)
+        total_profiles = len(set(selected_profiles))
+        fitting_type = None
+
+        if total_selected_objs == 1:
+            fitting_type = "OBSTRUCTION"
+        elif total_selected_objs == 2:
+            # Shorten the axis by the profile size to allow for fuzzy intersections
+            # e.g. if two ducts touch, we want a bend, not a cross.
+
+            axis1 = tool.Model.get_flow_segment_axis(selected_objs[0])
+            profile_size = max(selected_objs[0].dimensions.x, selected_objs[0].dimensions.y)
+            offset = (axis1[1] - axis1[0]).normalized() * profile_size
+            axis1 = (axis1[0] + offset, axis1[1] - offset)
+
+            axis2 = tool.Model.get_flow_segment_axis(selected_objs[1])
+            profile_size = max(selected_objs[1].dimensions.x, selected_objs[1].dimensions.y)
+            offset = (axis2[1] - axis2[0]).normalized() * profile_size
+            axis2 = (axis2[0] + offset, axis2[1] - offset)
+
+            angle = tool.Cad.angle_edges(axis1, axis2, signed=False, degrees=True)
+            is_parallel = tool.Cad.is_x(angle, (0, 180), tolerance=0.001)
+
+            if total_profiles == 1:
+                if is_parallel:
+                    return
+                intersect1, intersect2 = tool.Cad.intersect_edges(axis1, axis2)
+                is_on_axis1 = tool.Cad.is_point_on_edge(intersect1, axis1)
+                is_on_axis2 = tool.Cad.is_point_on_edge(intersect2, axis2)
+                if not is_on_axis1 and not is_on_axis2:
+                    fitting_type = "BEND"
+                elif is_on_axis1 and is_on_axis2:
+                    fitting_type = "CROSS"
+                else:
+                    fitting_type = "TEE"
+            elif total_profiles == 2:
+                if is_parallel:
+                    fitting_type = "TRANSITION"
+        elif total_selected_objs == 3:
+            if total_profiles > 1:
+                return
+
+            axis1 = tool.Model.get_flow_segment_axis(selected_objs[0])
+            axis2 = tool.Model.get_flow_segment_axis(selected_objs[1])
+            axis3 = tool.Model.get_flow_segment_axis(selected_objs[2])
+
+            angle12 = tool.Cad.angle_edges(axis1, axis2, signed=False, degrees=True)
+            angle13 = tool.Cad.angle_edges(axis1, axis3, signed=False, degrees=True)
+            angle21 = tool.Cad.angle_edges(axis2, axis1, signed=False, degrees=True)
+            angle23 = tool.Cad.angle_edges(axis2, axis3, signed=False, degrees=True)
+            is_parallel12 = tool.Cad.is_x(angle12, (0, 180), tolerance=0.001)
+            is_parallel13 = tool.Cad.is_x(angle13, (0, 180), tolerance=0.001)
+            is_parallel21 = tool.Cad.is_x(angle21, (0, 180), tolerance=0.001)
+            is_parallel23 = tool.Cad.is_x(angle23, (0, 180), tolerance=0.001)
+
+            if not all(is_parallel12, is_parallel13, is_parallel21, is_parallel23):
+                fitting_type = "WYE"
+
+        if not fitting_type:
+            return
+
+        print(fitting_type)
+
+
+class MepGenerator:
     def __init__(self, relating_type=None):
         self.relating_type = relating_type
 

src/blenderbim/blenderbim/bim/module/model/workspace.py

@@ -318,10 +318,20 @@ class BimToolUI:
             op.depth = cls.props.extrusion_depth
 
             add_layout_hotkey_operator(cls.layout, "Extend", "S_E", "")
-            add_layout_hotkey_operator(cls.layout, "Edit Axis", "A_E", "")
+
-            add_layout_hotkey_operator(cls.layout, "Butt", "S_T", "")
+            if AuthoringData.data["active_class"] in (
-            add_layout_hotkey_operator(cls.layout, "Mitre", "S_Y", "")
+                "IfcCableCarrierSegment",
-            add_layout_hotkey_operator(cls.layout, "Rotate 90", "S_R", bpy.ops.bim.rotate_90.__doc__)
+                "IfcCableSegment",
+                "IfcDuctSegment",
+                "IfcPipeSegment",
+            ):
+                add_layout_hotkey_operator(cls.layout, "Extend", "S_E", "")
+                add_layout_hotkey_operator(cls.layout, "Add Fitting", "S_F", "")
+            else:
+                add_layout_hotkey_operator(cls.layout, "Edit Axis", "A_E", "")
+                add_layout_hotkey_operator(cls.layout, "Butt", "S_T", "")
+                add_layout_hotkey_operator(cls.layout, "Mitre", "S_Y", "")
+                add_layout_hotkey_operator(cls.layout, "Rotate 90", "S_R", bpy.ops.bim.rotate_90.__doc__)
             add_layout_hotkey_operator(cls.layout, "Regen", "S_G", bpy.ops.bim.recalculate_profile.__doc__)
             row.operator("bim.extend_profile", icon="X", text="").join_type = ""
 
@@ -358,14 +368,6 @@ class BimToolUI:
         elif AuthoringData.data["active_class"] in ("IfcSpace",):
             add_layout_hotkey_operator(cls.layout, "Regen", "S_G", bpy.ops.bim.generate_space.__doc__)
 
-        elif AuthoringData.data["active_class"] in (
-            "IfcCableCarrierSegmentType",
-            "IfcCableSegmentType",
-            "IfcDuctSegmentType",
-            "IfcPipeSegmentType",
-        ):
-            add_layout_hotkey_operator(cls.layout, "Extend", "S_E", "")
-
         elif (
             (RoofData.is_loaded or not RoofData.load())
             and RoofData.data["pset_data"]
@@ -631,6 +633,8 @@ class Hotkey(bpy.types.Operator, tool.Ifc.Operator):
             bpy.ops.bim.flip_wall()
         elif self.active_class in ("IfcWindow", "IfcWindowStandardCase", "IfcDoor", "IfcDoorStandardCase"):
             bpy.ops.bim.flip_fill()
+        elif self.active_class in ("IfcDuctSegment", "IfcPipeSegment", "IfcCableCarrierSegment", "IfcCableSegment"):
+            bpy.ops.bim.fit_flow_segments()
 
     def hotkey_S_G(self):
         if not bpy.context.selected_objects:

src/blenderbim/blenderbim/tool/model.py

@@ -495,6 +495,17 @@ class Model(blenderbim.core.tool.Model):
                 items.append(item.FirstOperand)
         return booleans
 
+    @classmethod
+    def get_flow_segment_axis(cls, obj):
+        z_values = [v[2] for v in obj.bound_box]
+        return (obj.matrix_world @ Vector((0, 0, min(z_values))), obj.matrix_world @ Vector((0, 0, max(z_values))))
+
+    @classmethod
+    def get_flow_segment_profile(cls, element):
+        material = ifcopenshell.util.element.get_material(element, should_skip_usage=True)
+        if material and material.is_a("IfcMaterialProfileSet") and len(material.MaterialProfiles) == 1:
+            return material.MaterialProfiles[0].Profile
+
     @classmethod
     def get_usage_type(cls, element):
         material = ifcopenshell.util.element.get_material(element, should_inherit=False)