[IfcOpenShell][BlenderBIM] Creating an IfcGrid,IfcBuildingStorey,IfcSlab,IfcWall and youtube demo.

C by Coen on 28 Jul 2022, edited 2 Jan 2024 # +1 votes

After reading this thread and seeing this post on a Freecad forum from 2016.

It made me wonder if I could create an .ifc with Python starting from the basics with a grid.

Conclusion, it seems I can, I barely changed the script and loaded the .ifc in BlenderBIM

Here is the python code:

<summary>See the python code</summary>


import os

import sys

import time

import uuid

import math


import ifcopenshell


O = 0., 0., 0.

X = 1., 0., 0.

Y = 0., 1., 0.

Z = 0., 0., 1.


create_guid = lambda: ifcopenshell.guid.compress(uuid.uuid1().hex)




file_name = 'grid.ifc'

timestamp = time.time()

timestring = time.strftime("%Y-%m-%dT%H:%M:%S", time.gmtime(timestamp))

creator = "C. Claus"

organization = "Claus aannemingsmaatschappij"

application, application_version = "IfcOpenShell", "0.5"

project_globalid, project_name = create_guid(), "Grid"




# open for Blank

ifc_file = ifcopenshell.file()




#=============================================


org = ifc_file.createIfcOrganization()

org.Name = organization


app = ifc_file.createIfcApplication()

app.ApplicationDeveloper = org

app.Version = "3.2"

app.ApplicationFullName = "BlenderBIM"


person = ifc_file.createIfcPerson()

person.FamilyName="C. Claus"




person_org= ifc_file.createIfcPersonAndOrganization()

person_org.ThePerson=person

person_org.TheOrganization=org


owner_hist= ifc_file.createIfcOwnerHistory()

owner_hist.OwningUser = person_org

owner_hist.OwningApplication = app

owner_hist.ChangeAction= "NOCHANGE"

owner_hist.CreationDate= int(time.time())


#  Global unit definitions

LengthUnit = ifc_file.createIfcSIUnit()

LengthUnit.UnitType = "LENGTHUNIT"

LengthUnit.Prefix = "MILLI"

LengthUnit.Name="METRE"


#AreaUnit = ifc_file.createIfcSIUnit("AREAUNIT" , None, "SQUARE_METRE")

AreaUnit = ifc_file.createIfcSIUnit()

AreaUnit.UnitType = "AREAUNIT"

AreaUnit.Name="SQUARE_METRE"




VolumeUnit = ifc_file.createIfcSIUnit()

VolumeUnit.UnitType = "VOLUMEUNIT"

VolumeUnit.Name="CUBIC_METRE"




PlaneAngleUnit = ifc_file.createIfcSIUnit()

PlaneAngleUnit.UnitType = "PLANEANGLEUNIT"

PlaneAngleUnit.Name  ="RADIAN"


AngleUnit = ifc_file.createIfcMeasureWithUnit()

AngleUnit.UnitComponent =PlaneAngleUnit 

AngleUnit.ValueComponent = ifc_file.createIfcPlaneAngleMeasure(math.pi/180)




DimExp = ifc_file.createIfcDimensionalExponents(0,0,0,0,0,0,0)




ConvertBaseUnit = ifc_file.createIfcConversionBasedUnit()

ConvertBaseUnit.Dimensions = DimExp

ConvertBaseUnit.UnitType="PLANEANGLEUNIT"

ConvertBaseUnit.Name="DEGREE"

ConvertBaseUnit.ConversionFactor = AngleUnit




UnitAssignment=ifc_file.createIfcUnitAssignment([LengthUnit , AreaUnit , VolumeUnit ,ConvertBaseUnit])


axis_X = ifc_file.createIfcDirection(X)

axis_Y = ifc_file.createIfcDirection(Y)

axis_Z = ifc_file.createIfcDirection(Z)

Pnt_O = ifc_file.createIfcCartesianPoint(O)




# Defining project and representation contexts 

WorldCoordinateSystem = ifc_file.createIfcAxis2Placement3D()

WorldCoordinateSystem.Location=Pnt_O

WorldCoordinateSystem.Axis = axis_Z

WorldCoordinateSystem.RefDirection = axis_X


context = ifc_file.createIfcGeometricRepresentationContext()

context.ContextType = "Model"

context.CoordinateSpaceDimension = 3

context.Precision = 1.e-05

context.WorldCoordinateSystem = WorldCoordinateSystem




footprint_context = ifc_file.createIfcGeometricRepresentationSubContext()

footprint_context.ContextIdentifier = 'FootPrint'

footprint_context.ContextType = "Model"

footprint_context.ParentContext = context

footprint_context.TargetView = 'MODEL_VIEW'


myProject = ifc_file.createIfcProject(create_guid())

myProject.OwnerHistory = owner_hist

myProject.Name = "Test Grid"

myProject.RepresentationContexts = [context]

myProject.UnitsInContext = UnitAssignment




# Defining site, building and first story ------------

site_placement = ifc_file.createIfcLocalPlacement()

site_placement.RelativePlacement=WorldCoordinateSystem

mySite = ifc_file.createIfcSite( create_guid() )

mySite.OwnerHistory = owner_hist

mySite.Name = "My Site"

mySite.ObjectPlacement = site_placement

mySite.CompositionType="ELEMENT"


building_placement = ifc_file.createIfcLocalPlacement()

building_placement.PlacementRelTo = site_placement

building_placement.RelativePlacement = WorldCoordinateSystem


myBuilding = ifc_file.createIfcBuilding( create_guid(), owner_hist )

myBuilding.Name = "Test Building"

myBuilding.ObjectPlacement = building_placement

myBuilding.CompositionType="ELEMENT"


floor1_placement = ifc_file.createIfcLocalPlacement()

floor1_placement.PlacementRelTo = building_placement

floor1_placement.RelativePlacement = WorldCoordinateSystem


floor1 = ifc_file.createIfcBuildingStorey( create_guid(), owner_hist )

floor1.Name = "Floor 1"

floor1.ObjectPlacement = floor1_placement

floor1.CompositionType="ELEMENT"

floor1.Elevation = 1000




container_project = ifc_file.createIfcRelAggregates(create_guid() , owner_hist)

container_project.Name="Project Container"

container_project.RelatingObject = myProject 

container_project.RelatedObjects = [mySite]


container_site = ifc_file.createIfcRelAggregates(create_guid() , owner_hist)

container_site.Name = "Site Container"

container_site.RelatingObject = mySite

container_site.RelatedObjects = [myBuilding] 


container_storey = ifc_file.createIfcRelAggregates(create_guid() , owner_hist)

container_storey.Name = "Building Container"

container_storey.RelatingObject = myBuilding

container_storey.RelatedObjects = [floor1] 




#####################################################

###       Defining the grid axes geometry         ###

#####################################################

GridXList = [   {'id':'1' , 'distance':0.0 } ,

                {'id':'2' , 'distance':4000.0}  ]


GridYList = [   {'id':'A' , 'distance':0.0 } ,

                {'id':'B' , 'distance':4000.0}  ]


xMin = GridXList[0]['distance']-2000.0 ; xMax =  GridXList[-1]['distance']+2000.0 

yMin =  GridYList[0]['distance']-2000.0 ; yMax =  GridYList[-1]['distance']+2000.0 




polylineSet = []

gridX = []

for iGrid in GridXList:

    pnt1 = ifc_file.createIfcCartesianPoint( (iGrid['distance'],yMin) )

    pnt2 = ifc_file.createIfcCartesianPoint( (iGrid['distance'],yMax) )

    Line = ifc_file.createIfcPolyline( [pnt1 , pnt2] )

    polylineSet.append(Line)

    grid = ifc_file.createIfcGridAxis()

    grid.AxisTag = iGrid['id']

    grid.AxisCurve = Line

    grid.SameSense = True

    gridX.append(grid)


gridY = []

for iGrid in GridYList:

    pnt1 = ifc_file.createIfcCartesianPoint( (xMin ,iGrid['distance']) )

    pnt2 = ifc_file.createIfcCartesianPoint( (xMax,iGrid['distance']) )

    Line = ifc_file.createIfcPolyline( [pnt1 , pnt2] )

    polylineSet.append(Line)

    grid = ifc_file.createIfcGridAxis()

    grid.AxisTag = iGrid['id']

    grid.AxisCurve = Line

    grid.SameSense = True

    gridY.append(grid)


# Defining the grid 

PntGrid = ifc_file.createIfcCartesianPoint( O )


myGridCoordinateSystem = ifc_file.createIfcAxis2Placement3D()

myGridCoordinateSystem.Location= PntGrid

myGridCoordinateSystem.Axis = axis_Z

myGridCoordinateSystem.RefDirection = axis_X


grid_placement = ifc_file.createIfcLocalPlacement()

grid_placement.PlacementRelTo = floor1_placement

grid_placement.RelativePlacement = myGridCoordinateSystem


grid_curvedSet =  ifc_file.createIfcGeometricCurveSet(polylineSet)


gridShape_Reppresentation = ifc_file.createIfcShapeRepresentation()

gridShape_Reppresentation.ContextOfItems = footprint_context

gridShape_Reppresentation.RepresentationIdentifier = 'FootPrint'

gridShape_Reppresentation.RepresentationType = 'GeometricCurveSet'

gridShape_Reppresentation.Items = [grid_curvedSet]


grid_Reppresentation = ifc_file.createIfcProductDefinitionShape()

grid_Reppresentation.Representations  = [gridShape_Reppresentation]


myGrid = ifc_file.createIfcGrid(create_guid() , owner_hist)

myGrid.ObjectPlacement = grid_placement

myGrid.Representation = grid_Reppresentation

myGrid.UAxes=gridX

myGrid.VAxes=gridY


# assignment to spatial structure ------------------------------------------ 

container_SpatialStructure= ifc_file.createIfcRelContainedInSpatialStructure(create_guid() , owner_hist)

container_SpatialStructure.Name='BuildingStoreyContainer'

container_SpatialStructure.Description = 'BuildingStoreyContainer for Elements'

container_SpatialStructure.RelatingStructure = floor1

container_SpatialStructure.RelatedElements = [myGrid]




file_path = "C:\\Algemeen\\07_prive\\08_ifc_bestanden\\"

file_ifc = file_path  + file_name

print (file_ifc)

ifc_file.write(file_ifc)

</details>

How would I add the grid letter and number visibility in BlenderBIM? Like it is in BIMVision

C by CadGiru on 28 Jul 2022 #

@Coen Is it an idea to start putting Snippets found here on the wiki?

T by theoryshaw on 28 Jul 2022 #

@CadGiru said:

@Coen Is it an idea to start putting Snippets found here on the wiki?

i like that idea. Posting them to our https://gitlab.com/osarch/Example_Files repo, i think would be a better idea.

...

@Coen noob question, is there anyway to run a script like this in BB... and have the results show 'live' in the 3D viewport? That is, instead of running the script, creating the IFC file, and then importing the IFC into BB.

C by Coen on 28 Jul 2022 #

@CadGiru said:

@Coen Is it an idea to start putting Snippets found here on the wiki?

That is probably a good idea,

@theoryshaw said:

@Coen noob question, is there anyway to run a script like this in BB... and have the results show 'live' in the 3D viewport? That is, instead of running the script, creating the IFC file, and then importing the IFC into BB.

Live interaction with BlenderBIM would be great. BIMVision has this feature when a change is detected in IFC it prompts you to load the new version. Would be cool if BlenderBIM could do the same. I don't know if this is hard thing to do. I should look into it, I vaguely remember someone already made this before....? Or I dreamt it.

T by theoryshaw on 28 Jul 2022 # +1 votes

How would I add the grid letter and number visibility in BlenderBIM? Like it is in BIMVision

How to do it via the UI...

C by Coen on 28 Jul 2022 # +1 votes

@theoryshaw

@Coen noob question, is there anyway to run a script like this in BB... and have the results show 'live' in the 3D viewport? That is, instead of running the script, creating the IFC file, and then importing the IFC into BB.

I was thinking about this, I think I'm almost there.

You could just put this line at the end of your script:


bpy.ops.bim.load_project(filepath=file_ifc)

And then then store the timestamp in a temporary variable, I need to do some more research on where it's stored usally in IFC and catch the exceptions, I now do relatively dumb string parsing, which is not really fool proof...


def get_timestamp():

    ifc_file = ifcopenshell.open(IfcStore.path)


    with open(IfcStore.path) as ifc_text:

        for line_no, line_file in enumerate(ifc_text):

            if line_no  == 3:

                if line_file.startswith("FILE_NAME"):

                    time_stamp = (line_file.split(',')[1])



    print (time_stamp)







get_timestamp()   



bpy.ops.bim.reload_ifc_file()

If the user clicks save project, or somehow it detects the ifc file is being overwritten. It should start comparing the time stamps, if a difference in time stampts is detected it should unload the old ifc and load the the new ifc.

C by Coen on 28 Jul 2022 #

Just created a little workaround, this works, but be very careful! it throws an entire blender collection away where the IFC is located. Only store things in IFC and don't save the Blender file.


project = ifc_file.by_type('IfcProject')


for i in project:

    collection_name = 'IfcProject/' + i.Name



collection = bpy.data.collections.get(str(collection_name))



for obj in collection.objects:

    bpy.data.objects.remove(obj, do_unlink=True)



bpy.data.collections.remove(collection)

bpy.ops.bim.load_project(filepath=file_ifc)

If you copy paste this at the end of your IfcOpenShell python scripts it automatically load the IFC file in BlenderBIM (Taking it you're coding in BlenderBIM ofcourse)..

T by theoryshaw on 28 Jul 2022 #

nice.. this noob will play around. :)

C by Coen on 28 Jul 2022 # +2 votes

Seems to work... ?

C by Coen on 1 Aug 2022, edited 1 Aug 2022 # +2 votes

Did some refactoring of creating an IfcGrid, now you can change the grid amount and grid distance through a function:

Code to be found here:

https://github.com/C-Claus/BlenderScripts/blob/master/BlenderBIMGrid/create_grid_refactored_clean.py

Some-auto generated results:

T by theoryshaw on 1 Aug 2022, edited 1 Aug 2022 #

@Coen said:

Next step, trying to create an IfcSlab through IfcOpenShell and add it to certain grid points. Probably worth another thread.

i'm curious how this could be codified in the IFC, to survive an IFC roundtrip.

Could it be through entitles like the following?

Unfortunately, it doesn't look like ifcopenshell supports the last three. Could be wrong. ping @aothms

T by theoryshaw on 1 Aug 2022 # +1 votes

@Coen a few suggestions here

I removed IFCPRODUCTDEFINITIONSHAPE and IFCGEOMETRICCURVESET, since the native gridlines in BB don't have these entities associated with them.

You might have had a good reason to include them, if so, please disregard. I'm mostly doing this for practice. :)

Best, Ryan

T by theoryshaw on 1 Aug 2022 # +1 votes

It also looks like the IFCLOCALPLACEMENT is different. Not sure which one's right... local placement confuses me a little.

In the create_grid_refactored_clean.py script...


  /*#101=IFCGRID('2dgA7o4TeHxRPiIF5$qabM',#5,$,$,$,#97,#100,(#46,#50,#54,#58),(#62,#66,#70,#74,#78,#82,#86,#90,#94),$,$);*/

    /*#97=IFCLOCALPLACEMENT(#38,#96);*/

      /*#38=IFCLOCALPLACEMENT(#32,#37);*/

        /*#32=IFCLOCALPLACEMENT(#26,#31);*/

          /*#26=IFCLOCALPLACEMENT($,#25);*/

            /*#25=IFCAXIS2PLACEMENT3D(#22,#23,#24);*/

              /*#22=IFCCARTESIANPOINT((0.,0.,0.));*/

              /*#23=IFCDIRECTION((0.,0.,1.));*/

              /*#24=IFCDIRECTION((1.,0.,0.));*/

          /*#31=IFCAXIS2PLACEMENT3D(#28,#29,#30);*/

            /*#28=IFCCARTESIANPOINT((0.,0.,0.));*/

            /*#29=IFCDIRECTION((0.,0.,1.));*/

            /*#30=IFCDIRECTION((1.,0.,0.));*/

        /*#37=IFCAXIS2PLACEMENT3D(#34,#35,#36);*/

          /*#34=IFCCARTESIANPOINT((0.,0.,0.));*/

          /*#35=IFCDIRECTION((0.,0.,1.));*/

          /*#36=IFCDIRECTION((1.,0.,0.));*/

      /*#96=IFCAXIS2PLACEMENT3D(#95,#16,#14);*/

        /*#95=IFCCARTESIANPOINT((0.,0.,0.));*/

        /*#16=IFCDIRECTION((0.,0.,1.));*/

        /*#14=IFCDIRECTION((1.,0.,0.));*/

In native BB....


#60=IFCGRID('1FWhmuU9jB0u2KIDhbgjcq',$,'Grid',$,$,#71,$,(#72,#76,#80),(#84,#88,#92),$,$);

  /*#71=IFCLOCALPLACEMENT(#47,#70);*/

    /*#47=IFCLOCALPLACEMENT($,#46);*/

      /*#46=IFCAXIS2PLACEMENT3D(#43,#44,#45);*/

        /*#43=IFCCARTESIANPOINT((0.,0.,0.));*/

        /*#44=IFCDIRECTION((0.,0.,1.));*/

        /*#45=IFCDIRECTION((1.,0.,0.));*/

    /*#70=IFCAXIS2PLACEMENT3D(#67,#68,#69);*/

      /*#67=IFCCARTESIANPOINT((0.,0.,0.));*/

      /*#68=IFCDIRECTION((0.,0.,1.));*/

      /*#69=IFCDIRECTION((1.,0.,0.));*/

C by Coen on 2 Aug 2022, edited 2 Aug 2022 # +1 votes

@theoryshaw

Thanks for the info, I thought BlenderBIM had no curve support? But it seem to export succesfully.

I am now placing beams on the grid as I seen in the code from @BIMrookie92

Some screenshots of auto generated results:

BlenderBIM is so insanely fast with creating an entire IFC model and loading it....When I click run script it almost creates the geometry instantly.

Also make it easy to place columns along a grid,

C by Coen on 3 Aug 2022 # +2 votes

@theoryshaw

i'm curious how this could be codified in the IFC, to survive an IFC roundtrip.

Me as well, the method I'm using now is just removing and rewriting the entire IFC in BlenderBIM. (seems to work, because BlenderBIM is insanely fast with loading an IFC).

I made some little experiments with a IfcWall and IfcSlab, but I barely can't find any good Python documentation on how to create geometry with IfcOpenShell... Or maybe I am looking in the wrong places?. The only sources I used are the FreeCAD Forum, snippets from this forum and ifcopenshell academy. It's a lot of trial and error... and reading BuildingSmart documentation and logically trying to translate it to python code.

Anyway some results:

IfcWall placement moves if you change the slab thickness.

C by Coen on 1 Aug 2022 #

Next step, trying to create an IfcSlab through IfcOpenShell and add it to certain grid points. Probably worth another thread.

T by theoryshaw on 3 Aug 2022, edited 3 Aug 2022 # +1 votes

Imagine if IFC allowed us to do this?! :)

C by Coen on 4 Aug 2022 #

I managed to get a slab and beam system to move along with the grid, probaly in a stupid way but it works.

Still don't know how to create a IfcWall from a curve2D in ifcopenshell. ?

C by Coen on 4 Aug 2022 #

Managed to create 1000 storey slabs. ?

Just amazing how fast BlenderBIM is with creating and loading...

C by Coen on 4 Aug 2022 # +5 votes

For now I finished playing around with ifcopenshell and python :-)

Here is the refactored code:

https://github.com/C-Claus/BlenderScripts/blob/master/BlenderBIMGrid/create_grid_with_slabs_and_building_stories.py

Removed a lot of stupid mistakes and unnecessary variables. Tried to keep it as simple as possible

Scripts allow for creation of grids/building storeys and IfcSlabs created in IfcOpenShell and loaded in BlenderBIM. I think it could maybe serve as a basis for other things? . I highly appreciate feedback :-).

And a screenshot:

Don't know if this is worth a youtube demo?

N by Nigel on 4 Aug 2022 # +2 votes

@Coen you do a lot of cool work, do the YouTube please. It helps people like me and closes off your mini project nicely

C by Coen on 6 Aug 2022 # +5 votes

It's kind of a challenge to create as much geometry as possible with as little config parameters as possible

N by Nigel on 7 Aug 2022 # +1 votes

Hi @Coen this is cool, I downloaded the earlier code that makes the grids and builds the floors, thank you. Now I'm really interested in how the walls get built

C by Coen on 18 Aug 2022 # +8 votes

@Nigel

@Coen you do a lot of cool work, do the YouTube please. It helps people like me and closes off your mini project nicely

Thanks, I made a youtube video.

The code is to be found here.

I tested it thoroughly, everything in this image should be easily adjustable through the python script, with the following parameters:


filename                    = "demo.ifc"

folder_path                 = "C:\\Algemeen\\07_prive\\08_ifc_bestanden\\"


building_storeys_amount     = 2         # is the n number of building storeys, can't be 0 or less than 0

elevation                   = 0.0       # is where the first of the building storeys start

building_storey_height      = 3000      # is the equal distance between the building storeys



grids_x_direction_amount    = 5        # is the n number of grids in x direction

grids_y_direction_amount    = 5         # is the n number of grids in y direction

grids_x_distance_between    = 1000.0     # is the distance between the x grids, always should be a float

grids_y_distance_between    = 1000.0    # is the distance between the y grids, always should be a float

grid_extends                = 2000.0    # is the distance on how much the grid extends


slab_thickness              = 200.0  

wall_interior_thickness     = 200.0

wall_exterior_thickness     = 100.0

wall_covering_thickness     = 150.0

cavity_thickness            = 200.0

slab_covering_thickness     = 150.0

foundation_beam_height      = 1000.0

I made this script because I wanted to learn ifcopenshell, the idea was it to keep it as simple as possible so end users could maybe one day make a parametric grid, building storey, walls, which are modular. Everything is referenced from the (0,0,0) point.

I don't know where to take it from here, I could start coding an entire building with ifcopenshell, but the practicality of it seem to get lost.

Plus the homemaker add-on from @brunopostle already does this way better :-).

All the sources for the ifcopenshell code I uses were relatively old, forum posts from 2015 and such.

But this code could serve to make a structural basis for modeling, or for people who want to learn ifcopenshell as I did myself.

M by Moult on 19 Aug 2022 # +1 votes

This would be great to share on social media! By the way, IfcGridPlacement would be how to link objects to a grid's placement. However, it is not supported in IfcOpenShell.