viewer.py

# ref: https://github.com/tpaviot/pythonocc-core/issues/565
import OCC.Core.gp
import OCC.Core.Geom

import OCC.Core.Bnd
import OCC.Core.BRepBndLib

import OCC.Core.BRep
import OCC.Core.BRepPrimAPI
import OCC.Core.BRepAlgoAPI
import OCC.Core.BRepBuilderAPI

import OCC.Core.GProp
import OCC.Core.BRepGProp

import OCC.Core.TopoDS
import OCC.Core.TopExp
import OCC.Core.TopAbs


import ifcopenshell
import ifcopenshell.geom

# Specify to return pythonOCC shapes from ifcopenshell.geom.create_shape()
settings = ifcopenshell.geom.settings()
settings.set(settings.USE_PYTHON_OPENCASCADE, True)

# Initialize a graphical display window
occ_display = ifcopenshell.geom.utils.initialize_display()
#ifcopenshell.geom.utils.main_loop()

# Open the IFC file using IfcOpenShell
ifc_file = ifcopenshell.open("IfcOpenHouse_IFC2x3.ifc")

# Display the geometrical contents of the file using Python OpenCascade
products = ifc_file.by_type("IfcProduct")
for product in products:
    if product.is_a("IfcOpeningElement"): continue
    if product.Representation:
        shape = ifcopenshell.geom.create_shape(settings, product).geometry
        display_shape = ifcopenshell.geom.utils.display_shape(shape)
        if product.is_a("IfcPlate"):
            # Plates are the transparent parts of the window assembly
            # in the IfcOpenHouse model
            ifcopenshell.geom.utils.set_shape_transparency(display_shape, 0.8)
    
# Wait for user input and erase the display
##raw_input()
occ_display.EraseAll()

# Get a list of all walls in the file
walls = ifc_file.by_type("IfcWall")

# Create a list of wall representation shapes
# and compute the bounding box of these shapes
wall_shapes = []
bbox = OCC.Core.Bnd.Bnd_Box()
for wall in walls:
    shape = ifcopenshell.geom.create_shape(settings, wall).geometry
    
    wall_shapes.append((wall, shape))
    OCC.Core.BRepBndLib.brepbndlib_Add(shape, bbox)    
    
    ifcopenshell.geom.utils.display_shape(shape)
    
# Calculate the center/average of the bounding box
bounding_box_center = ifcopenshell.geom.utils.get_bounding_box_center(bbox)
print ("Bounding box center: %.2f %.2f %.2f" % 
    bounding_box_center.X(), 
    bounding_box_center.Y(),
    bounding_box_center.Z())

occ_display.DisplayMessage(bounding_box_center, "Center", update=True)

##raw_input()
occ_display.EraseAll()

occ_display.DisplayMessage(bounding_box_center, "Center", update=True)

# Now create halfspace solids from the inner faces of the wall
halfspaces = []
for wall, shape in wall_shapes:
    exp = OCC.Core.TopExp.TopExp_Explorer(shape, OCC.Core.TopAbs.TopAbs_FACE)
    while exp.More():
        face = OCC.Core.TopoDS.topods.Face(exp.Current())
        exp.Next()
        surf = OCC.Core.BRep.BRep_Tool.Surface(face)
        obj = surf.GetObject()
        assert obj.DynamicType().GetObject().Name() == "Geom_Plane"
        
        plane = OCC.Core.Geom.Handle_Geom_Plane_DownCast(surf).GetObject()
        
        if plane.Axis().Direction().Z() == 0:
            face_bbox = OCC.Core.Bnd.Bnd_Box()
            OCC.Core.BRepBndLib.brepbndlib_Add(face, face_bbox)
            face_center = ifcopenshell.geom.utils.get_bounding_box_center(face_bbox).XYZ()
            
            face_normal = plane.Axis().Direction().XYZ()
            face_towards_center = bounding_box_center.XYZ() - face_center
            face_towards_center.Normalize()
            
            dot = face_towards_center.Dot(face_normal)
            
            if dot < -0.8:
                
                ifcopenshell.geom.utils.display_shape(face)
                
                face_plane = plane.Pln()
                new_face = OCC.Core.BRepBuilderAPI.BRepBuilderAPI_MakeFace(face_plane).Face()
                halfspace = OCC.Core.BRepPrimAPI.BRepPrimAPI_MakeHalfSpace(new_face, bounding_box_center).Solid()
                halfspaces.append(halfspace)

##raw_input()
occ_display.EraseAll()

# Create halfspace solids from the bottom faces of the roofs
roofs = ifc_file.by_type("IfcRoof")
for roof in roofs:
    shape = ifcopenshell.geom.create_shape(settings, roof).geometry
    
    exp = OCC.Core.TopExp.TopExp_Explorer(shape, OCC.Core.TopAbs.TopAbs_FACE)
    while exp.More():
        face = OCC.Core.TopoDS.topods.Face(exp.Current())
        exp.Next()
        surf = OCC.Core.BRep.BRep_Tool.Surface(face)
        plane = OCC.Core.Geom.Handle_Geom_Plane_DownCast(surf).GetObject()
        
        assert obj.DynamicType().GetObject().Name() == "Geom_Plane"
        if plane.Axis().Direction().Z() > 0.7:
            face_plane = plane.Pln()
            new_face = OCC.Core.BRepBuilderAPI.BRepBuilderAPI_MakeFace(face_plane).Face()
            halfspace = OCC.Core.BRepPrimAPI.BRepPrimAPI_MakeHalfSpace(new_face, bounding_box_center).Solid()
            halfspaces.append(halfspace)
            
# Create an initial box from which to cut the halfspaces
common_shape = OCC.Core.BRepPrimAPI.BRepPrimAPI_MakeBox(OCC.Core.gp.gp_Pnt(-10, -10, 0), OCC.Core.gp.gp_Pnt(10, 10, 10)).Solid()
for halfspace in halfspaces:
    common_shape = OCC.Core.BRepAlgoAPI.BRepAlgoAPI_Common(common_shape, halfspace).Shape()

ifcopenshell.geom.utils.display_shape(common_shape)

# Calculate the volume properties of the resulting space shape
props = OCC.Core.GProp.GProp_GProps()
OCC.Core.BRepGProp.brepgprop_VolumeProperties(shape, props)
print ("Space volume: %.3f cubic meter" % props.Mass())

# Enter the main loop so that the user can navigate
ifcopenshell.geom.utils.main_loop()