From eb0f2de197c94e18d6eed83e56351e1c189e07ed Mon Sep 17 00:00:00 2001
From: Dion Moult <dion@thinkmoult.com>
Date: Mon, 21 Dec 2020 18:26:39 +1100
Subject: [PATCH] New snap spaces together utility for cleaning up spaces for
 energy modeling

---
 .../blenderbim/bim/__init__.py                |  1 +
 .../blenderbim/bim/operator.py                | 46 +++++++++++++++++++
 src/ifcblenderexport/blenderbim/bim/ui.py     |  2 +
 3 files changed, 49 insertions(+)

diff --git a/src/ifcblenderexport/blenderbim/bim/__init__.py b/src/ifcblenderexport/blenderbim/bim/__init__.py
index d2b38f8258..8cdb13edd9 100644
--- a/src/ifcblenderexport/blenderbim/bim/__init__.py
+++ b/src/ifcblenderexport/blenderbim/bim/__init__.py
@@ -238,6 +238,7 @@ if bpy is not None:
         operator.ExecuteBlenderClash,
         operator.CleanWireframes,
         operator.LinkIfc,
+        operator.SnapSpacesTogether,
         prop.StrProperty,
         prop.Attribute,
         prop.MaterialLayer,
diff --git a/src/ifcblenderexport/blenderbim/bim/operator.py b/src/ifcblenderexport/blenderbim/bim/operator.py
index f6474d0d68..15aaee35b6 100644
--- a/src/ifcblenderexport/blenderbim/bim/operator.py
+++ b/src/ifcblenderexport/blenderbim/bim/operator.py
@@ -5010,3 +5010,49 @@ class LinkIfc(bpy.types.Operator):
     def invoke(self, context, event):
         context.window_manager.fileselect_add(self)
         return {"RUNNING_MODAL"}
+
+
+class SnapSpacesTogether(bpy.types.Operator):
+    bl_idname = "bim.snap_spaces_together"
+    bl_label = "Snap Spaces Together"
+
+    def execute(self, context):
+        threshold = 0.5
+        processed_polygons = set()
+        for obj in bpy.context.selected_objects:
+            if obj.type != "MESH":
+                continue
+            for polygon in obj.data.polygons:
+                center = obj.matrix_world @ polygon.center
+                distance = None
+                for obj2 in bpy.context.selected_objects:
+                    if obj2 == obj or obj.type != "MESH":
+                        continue
+                    result = obj2.ray_cast(
+                        obj2.matrix_world.inverted() @ center,
+                        polygon.normal,
+                        distance=threshold
+                    )
+                    if not result[0]:
+                        continue
+                    hit = obj2.matrix_world @ result[1]
+                    distance = (hit - center).length / 2
+                    if distance < 0.01:
+                        distance = None
+                        break
+
+                    if (obj2.name, result[3]) in processed_polygons:
+                        distance *= 2
+                        continue
+
+                    offset = polygon.normal * distance * -1
+                    processed_polygons.add((obj2.name, result[3]))
+                    for v in obj2.data.polygons[result[3]].vertices:
+                        obj2.data.vertices[v].co += offset
+                    break
+                if distance:
+                    offset = polygon.normal * distance
+                    processed_polygons.add((obj.name, polygon.index))
+                    for v in polygon.vertices:
+                        obj.data.vertices[v].co += offset
+        return {"FINISHED"}
diff --git a/src/ifcblenderexport/blenderbim/bim/ui.py b/src/ifcblenderexport/blenderbim/bim/ui.py
index 91b23aa6cd..01eb0d76a3 100644
--- a/src/ifcblenderexport/blenderbim/bim/ui.py
+++ b/src/ifcblenderexport/blenderbim/bim/ui.py
@@ -2525,6 +2525,8 @@ class BIM_PT_misc_utilities(Panel):
         row.operator("bim.set_override_colour")
         row = layout.row(align=True)
         row.operator("bim.set_viewport_shadow_from_sun")
+        row = layout.row(align=True)
+        row.operator("bim.snap_spaces_together")
 
 
 class BIM_PT_debug(Panel):