IfcOpenshell: How to: an IfcBeamTypeInstance using an IfcProfile with IfcParametrizedProfileDef?

C by Coen on 6 Nov 2022, edited 29 Nov 2022 #

My attempt has been as following:

Tried to create an IfcProfile using ifcopenshell.api.

Looked here:

https://sourcegraph.com/search?q=context:global+profile+repo:%5Egithub%5C.com/IfcOpenShell/IfcOpenShell%24+file:src/ifcopenshell-python&patternType=standard

Read the BS documentation:

https://standards.buildingsmart.org/IFC/DEV/IFC4_3/RC2/HTML/schema/ifcmaterialresource/lexical/ifcmaterialprofile.htm

Tried to create a IfcBeamType instance with IfcMaterial:


import ifcopenshell.api


element_name='my_beam'


ifc_file = ifcopenshell.api.run("project.create_file")

project = ifcopenshell.api.run("root.create_entity", ifc_file, ifc_class="IfcProject", name="BlenderBIM Demo")


ifcopenshell.api.run( "project.assign_declaration", ifc_file, definition=project, relating_context=project)

ifcopenshell.api.run("unit.assign_unit", ifc_file, length={"is_metric": True, "raw": "METERS"})


material = ifcopenshell.api.run("material.add_material", ifc_file, name='beam_material')


element = ifcopenshell.api.run("root.create_entity", ifc_file, ifc_class='IfcBeamType', name=element_name)


profile_1 = ifcopenshell.api.run("material.assign_material", ifc_file, product=element, type="IfcMaterialProfileSetUsage")

profile_set = profile_1.RelatingMaterial


profile_2 = ifc_file.create_entity("IfcMaterialProfile")


ifcopenshell.api.run("project.assign_declaration", ifc_file, definition=element, relating_context=project)


ifc_file.write("D:\\02_ifc\\ifc_bibliotheek\\" + str(element_name) + ".ifc")

Quite clueless on how to tie it all together, this script just outputs this:


ISO-10303-21;

HEADER;

FILE_DESCRIPTION(('ViewDefinition[DesignTransferView]'),'2;1');

FILE_NAME('/dev/null','2022-11-06T11:31:03+01:00',(),(),'IfcOpenShell v0.7.0-cdde5366','IfcOpenShell v0.7.0-cdde5366','Nobody');

FILE_SCHEMA(('IFC4'));

ENDSEC;

DATA;

#1=IFCPROJECT('3NWCe2Fg16oO7d$m1LJcmY',$,'BlenderBIM Demo',$,$,$,$,$,#6);

#2=IFCRELDECLARES('0WOKmCVaz6$QsPWDCFj_FP',$,$,$,#1,(#8,#1));

#3=IFCSIUNIT(*,.LENGTHUNIT.,$,.METRE.);

#4=IFCSIUNIT(*,.AREAUNIT.,$,.SQUARE_METRE.);

#5=IFCSIUNIT(*,.VOLUMEUNIT.,$,.CUBIC_METRE.);

#6=IFCUNITASSIGNMENT((#4,#5,#3));

#7=IFCMATERIAL('beam_material',$,$);

#8=IFCBEAMTYPE('2CPnfvwOT6O9ZQyImvzlxU',$,'my_beam',$,$,$,$,$,$,.NOTDEFINED.);

#9=IFCMATERIALPROFILESET($,$,$,$);

#10=IFCMATERIALPROFILESETUSAGE(#9,$,$);

#11=IFCRELASSOCIATESMATERIAL('0LU7BOA5v1h9_90260WfJ0',$,$,$,(#8),#10);

#12=IFCMATERIALPROFILE($,$,$,$,$,$);

ENDSEC;

END-ISO-10303-21;

Somehow I need to define the IfcParametrizedProfileDef somewhere, hardcoded the X and Y dimensions, say to the IfcBeamType instance, you are now using an IfcProfile..

Is there a very simple example script somewhere?

T by theoryshaw on 6 Nov 2022 # +1 votes

This might help:

https://github.com/IfcOpenShell/IfcOpenShell/blob/v0.7.0/src/blenderbim/scripts/generate_demo_library.py

T by theoryshaw on 6 Nov 2022 # +1 votes

and also:

https://github.com/IfcOpenShell/IfcOpenShell/blob/v0.7.0/src/blenderbim/scripts/generate_steel_profiles_library.py

C by Coen on 6 Nov 2022 #

@theoryshaw

Thanks! I was looking for that, finally I understand it,


import ifcopenshell.api




element_name='my_beam'

ifc_file = ifcopenshell.api.run("project.create_file")

project = ifcopenshell.api.run("root.create_entity", ifc_file, ifc_class="IfcProject", name="BlenderBIM Demo")


ifcopenshell.api.run( "project.assign_declaration", ifc_file, definition=project, relating_context=project)

ifcopenshell.api.run("unit.assign_unit", ifc_file, length={"is_metric": True, "raw": "METERS"})


model = ifcopenshell.api.run("context.add_context", ifc_file, context_type="Model")

plan = ifcopenshell.api.run("context.add_context", ifc_file, context_type="Plan")

representations = {

    "body": ifcopenshell.api.run(

        "context.add_context",

        ifc_file,

        context_type="Model",

        context_identifier="Body",

        target_view="MODEL_VIEW",

        parent=model,

    ),

    "annotation": ifcopenshell.api.run(

        "context.add_context",

        ifc_file,

        context_type="Plan",

        context_identifier="Annotation",

        target_view="PLAN_VIEW",

        parent=plan,

    ),

}




material = ifcopenshell.api.run("material.add_material", ifc_file, name='beam_material')

profile = ifc_file.create_entity("IfcRectangleProfileDef", ProfileType="AREA", XDim=0.5, YDim=0.6)


element = ifcopenshell.api.run("root.create_entity", ifc_file, ifc_class='IfcBeamType', name=element_name)

rel = ifcopenshell.api.run("material.assign_material", ifc_file, product=element, type="IfcMaterialProfileSet")

profile_set = rel.RelatingMaterial

material_profile = ifcopenshell.api.run( "material.add_profile", ifc_file, profile_set=profile_set, material=material)

ifcopenshell.api.run("material.assign_profile", ifc_file, material_profile=material_profile, profile=profile)

ifcopenshell.api.run("project.assign_declaration", ifc_file, definition=element, relating_context=project)


ifc_file.write("D:\\02_ifc\\ifc_bibliotheek\\" + str(element_name) + ".ifc")

outputs:


ISO-10303-21;

HEADER;

FILE_DESCRIPTION(('ViewDefinition[DesignTransferView]'),'2;1');

FILE_NAME('/dev/null','2022-11-06T18:14:10+01:00',(),(),'IfcOpenShell v0.7.0-cdde5366','IfcOpenShell v0.7.0-cdde5366','Nobody');

FILE_SCHEMA(('IFC4'));

ENDSEC;

DATA;

#1=IFCPROJECT('2prh7Q8cv0gQP0cEVv3X5i',$,'BlenderBIM Demo',$,$,$,$,(#11,#15),#6);

#2=IFCRELDECLARES('2$qNb5ZJrAkwtlKF2_xIcw',$,$,$,#1,(#1,#20));

#3=IFCSIUNIT(*,.LENGTHUNIT.,$,.METRE.);

#4=IFCSIUNIT(*,.AREAUNIT.,$,.SQUARE_METRE.);

#5=IFCSIUNIT(*,.VOLUMEUNIT.,$,.CUBIC_METRE.);

#6=IFCUNITASSIGNMENT((#5,#3,#4));

#7=IFCCARTESIANPOINT((0.,0.,0.));

#8=IFCDIRECTION((0.,0.,1.));

#9=IFCDIRECTION((1.,0.,0.));

#10=IFCAXIS2PLACEMENT3D(#7,#8,#9);

#11=IFCGEOMETRICREPRESENTATIONCONTEXT($,'Model',3,1.E-05,#10,$);

#12=IFCCARTESIANPOINT((0.,0.,0.));

#13=IFCDIRECTION((1.,0.,0.));

#14=IFCAXIS2PLACEMENT2D(#12,#13);

#15=IFCGEOMETRICREPRESENTATIONCONTEXT($,'Plan',2,1.E-05,#14,$);

#16=IFCGEOMETRICREPRESENTATIONSUBCONTEXT('Body','Model',*,*,*,*,#11,$,.MODEL_VIEW.,$);

#17=IFCGEOMETRICREPRESENTATIONSUBCONTEXT('Annotation','Plan',*,*,*,*,#15,$,.PLAN_VIEW.,$);

#18=IFCMATERIAL('beam_material',$,$);

#19=IFCRECTANGLEPROFILEDEF(.AREA.,$,$,0.5,0.6);

#20=IFCBEAMTYPE('3NjduEPSD8rO4_gUk3YfbZ',$,'my_beam',$,$,$,$,$,$,.NOTDEFINED.);

#21=IFCMATERIALPROFILESET($,$,(#23),$);

#22=IFCRELASSOCIATESMATERIAL('1$CC$$22r6Cgn9FedD7wRG',$,$,$,(#20),#21);

#23=IFCMATERIALPROFILE($,$,#18,#19,$,$);

ENDSEC;

END-ISO-10303-21;

In BlenderBIM:

How to add an IfcType instance with python?

T by theoryshaw on 6 Nov 2022, edited 6 Nov 2022 #

not sure, does this help? https://github.com/IfcOpenShell/IfcOpenShell/blob/cbd9c898c37bb44500bf3be39c87241cfd8a4fe1/src/blenderbim/blenderbim/bim/module/model/profile.py#L142-L189

M by Moult on 6 Nov 2022 # +2 votes

You're almost there, you're just missing at the end:


# Add occurrence based on type

occurrence = ifcopenshell.api.run("root.create_entity", ifc_file, ifc_class="IfcBeam", name=element_name)

ifcopenshell.api.run("type.assign_type", ifc_file, related_object=occurrence, relating_type=element)

representation = ifcopenshell.api.run("geometry.add_profile_representation", ifc_file, context=contexts["body"], profile=profile, depth=3)

ifcopenshell.api.run("geometry.assign_representation", ifc_file, product=occurrence, representation=representation)

Also you can do this which is simpler:


material_profile = ifcopenshell.api.run("material.add_profile", ifc_file, profile_set=profile_set, material=material, profile=profile)

Don't use project.assign_declaration it is not necessary, you can delete every line that uses that. That's only used for asset library declarations.

C by Coen on 7 Nov 2022 #

@Moult

Thanks! how would I place the IfcElementType instance using XYZ coordinates?

M by Moult on 7 Nov 2022 #

Use geometry.edit_object_placement.

C by Coen on 7 Nov 2022, edited 7 Nov 2022 #

@Moult

Thank you. :-)

What does depth=3 do in ifcopenshell.api.run("geometry.add_profile_representation", ifc_file, context=contexts["body"], profile=profile, depth=3)?

And where is contexts defined in representation = ifcopenshell.api.run("geometry.add_profile_representation", ifc_file, context=contexts["body"], profile=profile, depth=3)

C by Coen on 7 Nov 2022 #

I changed this line

ifcopenshell.api.run("geometry.add_profile_representation", ifc_file, context=contexts["body"], profile=profile, depth=3)

to

representation = ifcopenshell.api.run("geometry.add_profile_representation", ifc_file, context=representations["body"], profile=profile, depth=3)

I have not defined an IfcBuildingStorey to place the beam in, but for some strange reason, when loading the created IFC in BlenderBIM my beam appears vertical:

C by Coen on 7 Nov 2022, edited 7 Nov 2022 #

How do I add an IfcBuilding, IfcSite and IfcBuildingStorey using the ifcopenshell.api?

I know i can do it with IfcOpenShell like following:


site_placement = create_ifclocalplacement(ifcfile)

site = ifcfile.createIfcSite(create_guid(), owner_history, "site", None, None, site_placement, None, None, "ELEMENT", None, None, None, None, None)


building_placement = create_ifclocalplacement(ifcfile, relative_to=site_placement)

building = ifcfile.createIfcBuilding(create_guid(), owner_history, 'osarch_building', None, None, building_placement, None, None, "ELEMENT", None, None, None)


storey_placement = create_ifclocalplacement(ifcfile, relative_to=building_placement)

building_storey = ifcfile.createIfcBuildingStorey(  create_guid(),

                                                            owner_history,

                                                            '0' + str(i) + '_building_storey',

                                                            None,

                                                            None, 

                                                            storey_placement,

                                                            None,

                                                            None,

                                                            "ELEMENT",

                                                            0)

        container_storey = ifcfile.createIfcRelAggregates(create_guid(), owner_history, "Building Container", None, building, [building_storey])

Not really clear to me how to translate this to the ifcopenshell.api

EDIT:

found it here in @Martin156131 thread:

https://community.osarch.org/discussion/1221/ifcopenshell-python-how-using-the-objectplacement-in-ifcwall#latest


site = run("root.create_entity", model, ifc_class="IfcSite", name="My Site")

building = run("root.create_entity", model, ifc_class="IfcBuilding", name="Building A")

storey = run("root.create_entity", model, ifc_class="IfcBuildingStorey", name="Ground Floor")

C by Coen on 7 Nov 2022 #

I have a working script, still need to figure out how to place the IfcElement correctly

Script to be found here:

https://github.com/C-Claus/BlenderScripts/blob/master/BlenderBIM_create_objects/create_beam.py

C by Coen on 7 Nov 2022 # +4 votes

This thread... I should just have went straight here: https://blenderbim.org/docs-python/ifcopenshell-python/code_examples.html#create-a-simple-model-from-scratch

M by Moult on 7 Nov 2022 #

The beam is vertical because all extrusions in IFC have the convention of extruding in the local Z axis. This is an awesome convention and makes a huge difference in the reliability of geometric analysis. So if you want the beam to be flat, just edit its ObjectPlacement matrix.

C by Coen on 8 Nov 2022 #


matrix = numpy.array(

            (

                (1.0, 0.0, 0.0, 2.0),

                (0.0, 1.0, 0.0, 1.0),

                (0.0, 0.0, 1.0, 1.0),

                (0.0, 0.0, 0.0, 1.0),

            )

        )



ifcopenshell.api.run("geometry.edit_object_placement",ifc_file, product=occurrence, matrix=matrix)

@Moult, thanks, never worked with numpy arrays, need to figure it out first.

C by Coen on 8 Nov 2022, edited 8 Nov 2022 #

Where is the length of the IfcBeamType instance defined in the ifcopenshell.api? Can't find it in the example scripts or documentation.

M by Moult on 8 Nov 2022 # +2 votes

The length is called depth=3 in the add_profile_representation call.

The matrix is a 4x4 matrix described here https://blenderbim.org/docs-python/ifcopenshell-python/geometry_processing.html#individual-processing

C by Coen on 8 Nov 2022 #

Yes, horizontal beam! @Moult Thanks for patiently answering all my ignorant questions.

C by Coen on 8 Nov 2022 # +3 votes

Getting the hang of it now


for i in range(0, 10, 1): 





    matrix_1 = numpy.array(

                (

                    (0.0, 0.0, 1.0, 0.0),

                    (0.0, 1.0, 0.0, i),

                    (1.0, 0.0, 0.0, 0.0),

                    (0.0, 0.0, 0.0, 1.0),

                )

            )



    matrix_1 = numpy.array(matrix_1)



    occurrence = ifcopenshell.api.run("root.create_entity", ifc_file, ifc_class="IfcBeam", name=element_name, )

    ifcopenshell.api.run("type.assign_type", ifc_file, related_object=occurrence, relating_type=element)

    representation = ifcopenshell.api.run("geometry.add_profile_representation", ifc_file, context=representations["body"], profile=profile, depth=5)

C by Coen on 8 Nov 2022 #

Okay, this is a lot of fun, paramatric foundation beam system.. code is a mess now, but it works.

C by Coen on 8 Nov 2022, edited 8 Nov 2022 # +2 votes

Next step, slab and walls.

EDIT:

https://github.com/C-Claus/BlenderScripts/blob/master/BlenderBIM_create_objects/create_beam_array.py

Also the beams should align neatly now within their constraint when changing the profile.

It all should work with only 5 config variables,:


beam_length_x = 1

beam_profile_y = 0.4

beam_profile_x = 0.5

beam_total_length_n_y = 10

beam_inbetween_distance = 3 #=beam_length_y = 3

M by Moult on 8 Nov 2022 #

If you can get the code working with an arbitrary polygonal profile (i.e. not only rectangular), then that would be super cool and we could reuse your code for a feature for exactly that.

C by Coen on 9 Nov 2022 # +1 votes

@Moult said:

If you can get the code working with an arbitrary polygonal profile (i.e. not only rectangular), then that would be super cool and we could reuse your code for a feature for exactly that.

I will attempt

G by Gorgious on 14 Nov 2022 # +4 votes

It seems we are set on a very similar journey currently @Coen. I've been reading your different endeavours with great interest, and I'd like to thank you for documenting it so thorougly. I've still got lots to learn, and it's great fun to see others taking baby steps around me :)

The example demo is great but I think we can do more, there are in fact a lot of hidden snippets in the codebase, it would be nice to document them a bit more in depth. I'll do what I can to help :)

C by Coen on 15 Nov 2022, edited 16 Nov 2022 #

@Gorgious

Thanks for the kind words. There's a lot of knowledge on this forum. Many people here know how to point you in the right direction, so I don't drown in reading boring documentation. I'd like to document it together somewhere in a coherent way with fun little practical code snippets. Just curious where there's a demand. Because most of the stuff I document I do it for myself.