05_create_space.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "0a2dbad2-d190-4718-a235-d22db269b2ec",
   "metadata": {},
   "outputs": [],
   "source": [
    "import OCC.Core.BRepBndLib\n",
    "\n",
    "import OCC.Core.BRep\n",
    "import OCC.Core.BRepPrimAPI\n",
    "import OCC.Core.BRepAlgoAPI\n",
    "import OCC.Core.BRepBuilderAPI\n",
    "\n",
    "import OCC.Core.GProp\n",
    "import OCC.Core.BRepGProp\n",
    "\n",
    "import ifcopenshell\n",
    "import ifcopenshell.geom\n",
    "\n",
    "# Specify to return pythonOCC shapes from ifcopenshell.geom.create_shape()\n",
    "settings = ifcopenshell.geom.settings()\n",
    "settings.set(settings.USE_PYTHON_OPENCASCADE, True)\n",
    "\n",
    "# Initialize the viewer\n",
    "from ifc_viewer import ifc_viewer        \n",
    "viewer = ifc_viewer()\n",
    "\n",
    "\n",
    "# Open the IFC file using IfcOpenShell\n",
    "ifc_file = ifcopenshell.open(\"models/IfcOpenHouse.ifc\")\n",
    "\n",
    "# Display the geometrical contents of the file using Python OpenCascade\n",
    "products = ifc_file.by_type(\"IfcProduct\")\n",
    "for product in products:\n",
    "    if product.is_a(\"IfcOpeningElement\"): continue\n",
    "    if product.Representation:\n",
    "        shape = ifcopenshell.geom.create_shape(settings, product)\n",
    "        viewer.Add(product, shape.geometry, shape.styles)\n",
    "\n",
    "viewer.Display()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "a33c4767-8a61-477d-adbc-bc48a023d2b8",
   "metadata": {},
   "outputs": [],
   "source": [
    "settings = ifcopenshell.geom.settings()\n",
    "settings.set(settings.USE_PYTHON_OPENCASCADE, True)\n",
    "settings.set(settings.DISABLE_OPENING_SUBTRACTIONS, True)\n",
    "\n",
    "viewer2 = ifc_viewer()\n",
    "\n",
    "# Get a list of all walls in the file\n",
    "walls = ifc_file.by_type(\"IfcWall\")\n",
    "\n",
    "# Create a list of wall representation shapes\n",
    "# and compute the bounding box of these shapes\n",
    "wall_shapes = []\n",
    "bbox = OCC.Core.Bnd.Bnd_Box()\n",
    "for wall in walls:\n",
    "    shape = ifcopenshell.geom.create_shape(settings, wall)\n",
    "    \n",
    "    wall_shapes.append((wall, shape))\n",
    "    OCC.Core.BRepBndLib.brepbndlib_Add(shape.geometry, bbox)    \n",
    "    \n",
    "    viewer2.Add(wall, shape.geometry, shape.styles)\n",
    "\n",
    "# Calculate the center/average of the bounding box\n",
    "bounding_box_center = ifcopenshell.geom.utils.get_bounding_box_center(bbox)\n",
    "print(\"Bounding box center: %.2f %.2f %.2f\" % (\n",
    "    bounding_box_center.X(), \n",
    "    bounding_box_center.Y(),\n",
    "    bounding_box_center.Z())\n",
    ")\n",
    "\n",
    "viewer2.DisplayShape([bounding_box_center])\n",
    "\n",
    "viewer2.Display()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "4d086160-ef1d-47a3-afad-e0945c8a5c30",
   "metadata": {},
   "outputs": [],
   "source": [
    "import OCC.Core.TopExp\n",
    "import OCC.Core.TopTools\n",
    "import OCC.Core.BRepTools\n",
    "import OCC.Core.TopoDS\n",
    "\n",
    "from OCC.Core.TopAbs import *\n",
    "\n",
    "def yield_subshapes(s, type=None, vertices=False):\n",
    "    \"\"\"\n",
    "    Based on type in `s` and additional keyword arguments\n",
    "    initialize an OCCT iterator or explorer and yield its\n",
    "    values.\n",
    "    \"\"\"\n",
    "    if isinstance(s, OCC.Core.TopTools.TopTools_IndexedMapOfShape):\n",
    "        for i in range(1, s.Size() + 1):\n",
    "            yield s.FindKey(i)\n",
    "        return\n",
    "    elif isinstance(s, OCC.Core.TopTools.TopTools_ListOfShape):\n",
    "        it = OCC.Core.TopTools.TopTools_ListIteratorOfListOfShape(s)\n",
    "    else:\n",
    "        if type is None:\n",
    "            if s.ShapeType() == TopAbs_WIRE:\n",
    "                it = OCC.Core.BRepTools.BRepTools_WireExplorer(s)\n",
    "            else:\n",
    "                it = OCC.Core.TopoDS.TopoDS_Iterator(s)\n",
    "        else:\n",
    "            it = OCC.Core.TopExp.TopExp_Explorer(s, type)\n",
    "    while it.More():\n",
    "        if isinstance(it, OCC.Core.BRepTools.BRepTools_WireExplorer) and vertices:\n",
    "            yield it.CurrentVertex()\n",
    "        elif hasattr(it, 'Value'):\n",
    "            yield it.Value()\n",
    "        else:\n",
    "            yield it.Current()\n",
    "        it.Next()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "27a6adee-d3c2-40ca-9289-163f73d283b4",
   "metadata": {},
   "outputs": [],
   "source": [
    "viewer3 = ifc_viewer()\n",
    "\n",
    "# Now create halfspace solids from the inner faces of the wall\n",
    "halfspaces = []\n",
    "for wall, shape in wall_shapes:\n",
    "    for face in yield_subshapes(shape.geometry, TopAbs_FACE):\n",
    "        surf = OCC.Core.BRep.BRep_Tool.Surface(face)\n",
    "        assert surf.DynamicType().Name() == \"Geom_Plane\"\n",
    "\n",
    "        P, V = OCC.Core.gp.gp_Pnt(), OCC.Core.gp.gp_Vec()\n",
    "        prop = OCC.Core.BRepGProp.BRepGProp_Face(face)\n",
    "        prop.Normal(0, 0, P, V)\n",
    "                    \n",
    "        if abs(V.Z()) < 1.e-5:\n",
    "            face_bbox = OCC.Core.Bnd.Bnd_Box()\n",
    "            OCC.Core.BRepBndLib.brepbndlib_Add(face, face_bbox)\n",
    "            face_center = ifcopenshell.geom.utils.get_bounding_box_center(face_bbox).XYZ()\n",
    "            \n",
    "            face_towards_center = bounding_box_center.XYZ() - face_center\n",
    "            face_towards_center.Normalize()\n",
    "            \n",
    "            dot = face_towards_center.Dot(V.XYZ())\n",
    "            \n",
    "            if dot < -0.8:\n",
    "                \n",
    "                viewer3.DisplayShape(face)\n",
    "                new_face = OCC.Core.BRepBuilderAPI.BRepBuilderAPI_MakeFace(surf, 1.e-5).Face()\n",
    "                halfspace = OCC.Core.BRepPrimAPI.BRepPrimAPI_MakeHalfSpace(new_face, bounding_box_center).Solid()\n",
    "                halfspaces.append(halfspace)\n",
    "\n",
    "viewer3.Display()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "914ac4a4-be90-40a8-b636-d40c9a69fbc8",
   "metadata": {},
   "outputs": [],
   "source": [
    "viewer4 = ifc_viewer()\n",
    "\n",
    "# Create halfspace solids from the bottom faces of the roofs\n",
    "roofs = ifc_file.by_type(\"IfcRoof\")\n",
    "for roof in roofs:\n",
    "    for roof_slab in roof.IsDecomposedBy[0].RelatedObjects:\n",
    "        shape = ifcopenshell.geom.create_shape(settings, roof_slab).geometry\n",
    "        \n",
    "        for face in yield_subshapes(shape, TopAbs_FACE):\n",
    "            surf = OCC.Core.BRep.BRep_Tool.Surface(face)\n",
    "            P, V = OCC.Core.gp.gp_Pnt(), OCC.Core.gp.gp_Vec()\n",
    "            prop = OCC.Core.BRepGProp.BRepGProp_Face(face)\n",
    "            prop.Normal(0, 0, P, V)\n",
    "            if V.Z() < -0.7:\n",
    "                new_face = OCC.Core.BRepBuilderAPI.BRepBuilderAPI_MakeFace(surf, 1.e-5).Face()\n",
    "                halfspace = OCC.Core.BRepPrimAPI.BRepPrimAPI_MakeHalfSpace(new_face, bounding_box_center).Solid()\n",
    "                halfspaces.append(halfspace)\n",
    "            \n",
    "# Create an initial box from which to cut the halfspaces\n",
    "common_shape = OCC.Core.BRepPrimAPI.BRepPrimAPI_MakeBox(OCC.Core.gp.gp_Pnt(-10, -10, 0), OCC.Core.gp.gp_Pnt(10, 10, 10)).Solid()\n",
    "for halfspace in halfspaces:\n",
    "    common_shape = OCC.Core.BRepAlgoAPI.BRepAlgoAPI_Common(common_shape, halfspace).Shape()    \n",
    "\n",
    "viewer4.DisplayShape(common_shape)\n",
    "\n",
    "# Calculate the volume properties of the resulting space shape\n",
    "props = OCC.Core.GProp.GProp_GProps()\n",
    "OCC.Core.BRepGProp.brepgprop_VolumeProperties(common_shape, props)\n",
    "print(\"Space volume: %.3f cubic meter\" % props.Mass())\n",
    "\n",
    "viewer4.Display()"
   ]
  }
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