OpenAI released a new flagship model, GPT 4o, also in the chat version. GPT4o is claimed to be faster and more efficient than its predecessor, GPT4. Importantly, it is available to all users, not only the premium ones. It is a good occasion to perform another IFC-generating experiment.
ChatGPT4 did well in our last experiment, but there is room for improvement. This time, we will test the newest ChatGPT4o and a technique called in-context learning. Specifically, one-shot learning. In in-context learning, the prompt (the message to the AI model) includes examples of desired outputs (or input-output pairs). In our case, in addition to the task description (“Generate an IFC model…”), the prompt will also contain a valid IFC schema. As there will be one example, we have one-shot learning.
Prerequisites
I will ask ChatGPT to create a simple model containing one concrete column (2 meters high, square cross-section 0.3 meters wide, located at point (0,0,0)).
As said, we will use a prompt engineering technique called one-shot learning. So the first prompt will contain an example of a valid IFC schema. I will use the extruded-solid model from the buildingSMART samples repository. (The model is by Thomas Liebich. I highly recommend his IFC Implementation Guide for understanding IFC better.)
After getting the output, I will copy the generated IFC schema, save it as a “.ifc” file, and check the model in a viewer (Xbim Xplorer).
If the viewer throws errors when opening the model, I will send them to ChatGPT, so it can iterate. I will also inform GPT if there are other types of issues spotted in the viewer (such as geometry not shown). But I will not provide GPT any “expert” guidance or IFC documentation. Just errors and visible issues to iterate. I will act as an “IFC newbie” and see if GPT can work everything out on its own.
For this experiment, I am using ChatGPT4o (gpt-4o).
Let’s start.
Iteration #1 – the first prompt and model
Me:
Prepare a complete, valid schema for a simple IFC (Industry Foundation Classes) model. The model should contain only one concrete column, which should be 2 meters high with a square cross-section 0.3 meters wide. The column should be located at point (0,0,0).
Below is an example of a valid IFC schema for a reference; you don't have to follow the schema exactly.ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]'
,'Comment [manual creation of example file]'
)
,'2;1');
/* NOTE standard header information according to ISO 10303-21 ---------------------------------- */
FILE_NAME(
'basic_shape_SweptSolid.ifc',
'2012-06-18T18:00:00',
('Thomas Liebich'),
('buildingSMART International'),
'IFC text editor',
'IFC text editor',
'reference file created for the IFC4 specification');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* --------------------------------------------------------------------------------------------- */
/* general entities required for all IFC data sets, defining the context for the exchange ------ */
#100= IFCPROJECT('0xScRe4drECQ4DMSqUjd6d',#110,'proxy with swept solid',$,$,$,$,(#201),#301);
/* single owner history sufficient if not otherwise required by the view definition ------------ */
/* provides the person and application creating the data set, and the time it is created ------- */
#110= IFCOWNERHISTORY(#111,#115,$,.ADDED.,1320688800,$,$,1320688800);
#111= IFCPERSONANDORGANIZATION(#112,#113,$);
#112= IFCPERSON($,'Liebich','Thomas',$,$,$,$,$);
#113= IFCORGANIZATION($,'buildingSMART International',$,$,$);
#115= IFCAPPLICATION(#113,'1.0','IFC text editor','ifcTE');
/* each IFC data set containing geometry has to define a geometric representation context ------ */
/* the attribute 'ContextType' has to be 'Model' for 3D model geometry ------------------------- */
#201= IFCGEOMETRICREPRESENTATIONCONTEXT($,'Model',3,1.0E-5,#210,$);
/* the attribute 'ContextIdentifier' has to be 'Body' for the main 3D shape representation ----- */
#202= IFCGEOMETRICREPRESENTATIONSUBCONTEXT('Body','Model',*,*,*,*,#201,$,.MODEL_VIEW.,$);
#210= IFCAXIS2PLACEMENT3D(#901,$,$);
/* each IFC data set containing geometry has to define at absolute minimum length and angle ---- */
/* here length is milli metre as SI unit, and plane angle is 'degree' as non SI unit ----------- */
#301= IFCUNITASSIGNMENT((#311,#312));
#311= IFCSIUNIT(*,.LENGTHUNIT.,.MILLI.,.METRE.);
#312= IFCCONVERSIONBASEDUNIT(#313,.PLANEANGLEUNIT.,'degree',#314);
#313= IFCDIMENSIONALEXPONENTS(0,0,0,0,0,0,0);
#314= IFCMEASUREWITHUNIT(IFCPLANEANGLEMEASURE(0.017453293),#315);
#315= IFCSIUNIT(*,.PLANEANGLEUNIT.,$,.RADIAN.);
/* each IFC data set containing elements in a building context has to include a building ------- */
/* at absolute minimum (could have a site and stories as well) --------------------------------- */
#500= IFCBUILDING('2FCZDorxHDT8NI01kdXi8P',$,'Test Building',$,$,#511,$,$,.ELEMENT.,$,$,$);
/* if the building is the uppermost spatial structure element it defines the absolut position -- */
#511= IFCLOCALPLACEMENT($,#512);
/* no rotation - z and x axes set to '$' are therefore identical to "world coordinate system" -- */
#512= IFCAXIS2PLACEMENT3D(#901,$,$);
/* if the building is the uppermost spatial structure element it is assigned to the project ---- */
#519= IFCRELAGGREGATES('2YBqaV_8L15eWJ9DA1sGmT',$,$,$,#100,(#500));
/* shared coordinates - it is permissable to share common instances to reduce file size -------- */
#901= IFCCARTESIANPOINT((0.,0.,0.));
#902= IFCDIRECTION((1.,0.,0.));
#903= IFCDIRECTION((0.,1.,0.));
#904= IFCDIRECTION((0.,0.,1.));
#905= IFCDIRECTION((-1.,0.,0.));
#906= IFCDIRECTION((0.,-1.,0.));
#907= IFCDIRECTION((0.,0.,-1.));
/* --------------------------------------------------------------------------------------------- */
/* proxy element with swept solid shape representation, assigned to the building --------------- */
#1000= IFCBUILDINGELEMENTPROXY('1kTvXnbbzCWw8lcMd1dR4o',$,'P-1','sample proxy',$,#1001,#1010,$,$);
/* proxy element placement relative to the building -------------------------------------------- */
#1001= IFCLOCALPLACEMENT(#511,#1002);
/* set local placement to 1 meter on x-axis, and 0 on y, and 0 on z axes ----------------------- */
/* no rotation - z and x axes set to '$' are therefore identical to those of building ---------- */
#1002= IFCAXIS2PLACEMENT3D(#1003,$,$);
#1003= IFCCARTESIANPOINT((1000.,0.,0.));
/* proxy element shape representation ---------------------------------------------------------- */
#1010= IFCPRODUCTDEFINITIONSHAPE($,$,(#1020));
/* a single shape representation of type 'SweptSolid' is included ------------------------------ */
#1020= IFCSHAPEREPRESENTATION(#202,'Body','SweptSolid',(#1021));
/* based on a profile (or cross section) of 1m by 1m being extruded by 2m ---------------------- */
#1021= IFCEXTRUDEDAREASOLID(#1022,$,#1034,2000.);
#1022= IFCRECTANGLEPROFILEDEF(.AREA.,'1m x 1m rectangle',$,1000.,1000.);
/* extrusion body is placed centric with no rotation inside the object coordinate placement ---- */
/* extrusion position z = default = (0.,0.,1.), x = default = (1.,0.,0.) ----------------------- */
/* the default position, i.e. no re-positioning of the results, hence the position is NIL ------ */
/* the extrusion if perpendicular to the profile - i.e. along the positive z-axis -------------- */
#1034= IFCDIRECTION((0.,0.,1.));
/* proxy element assigned to the building ------------------------------------------------------ */
#10000=IFCRELCONTAINEDINSPATIALSTRUCTURE('2TnxZkTXT08eDuMuhUUFNy',$,'Physical model',$,(#1000),#500);
ENDSEC;
END-ISO-10303-21;
ChatGPT:
Here's a complete and valid IFC schema for a simple model containing one concrete column, which is 2 meters high with a square cross-section 0.3 meters wide, located at point (0,0,0):ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_column.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Column model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Column Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Building and location */
#20 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #21, $, $, .ELEMENT., $, $, $);
#21 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#20));
/* Column definition */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#21, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #56, 2000.);
#53 = IFCRECTANGLEPROFILEDEF(.AREA., 'Square Profile', $, 300., 300.);
#56 = IFCDIRECTION((0., 0., 1.));
/* Spatial structure relation */
#60 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Column in Building', $, (#40), #20);
ENDSEC;
END-ISO-10303-21;
This schema defines a single concrete column with the specified dimensions and location, including all necessary project, building, and geometric context information.
This is a solid answer. The schema is almost completely valid. The spatial hierarchy and the geometry are already defined.
The output is influenced by the example, but it is not “mindlessly” copied. GPT introduced its own, pretty consistent order of entities and their numbering. It also made some mistakes. Less harmful: the first comment (“/* Project context and header information */”) is improper – the header is not defined in this fragment. The second one, spotted by the viewer validation, is a reference to a non-existing entity (#7 = IFCAXIS2PLACEMENT3D(#15, $, $) refers to #15, but it is not declared).
Following the experiment rules, let’s give the AI model a chance to refine.
Iteration #2 – correction
Me:
WARN Xbim.IO.Step21.XbimP21Parser
Entity #15 is referenced but could not be instantiated
ChatGPT:
It seems there's an issue with the referenced entity #15. I'll correct the references and ensure all necessary entities are instantiated properly. Here is the revised IFC schema:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_column.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Column model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Column Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCDIRECTION((1.,0.,0.));
#17 = IFCDIRECTION((0.,1.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
/* Building and location */
#20 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #21, $, $, .ELEMENT., $, $, $);
#21 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#20));
/* Column definition */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#21, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCRECTANGLEPROFILEDEF(.AREA., 'Square Profile', $, 300., 300.);
/* Spatial structure relation */
#60 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Column in Building', $, (#40), #20);
ENDSEC;
END-ISO-10303-21;
In this revised schema, the referenced entity #15 is instantiated correctly as an IFCCARTESIANPOINT, which is then used in IFCAXIS2PLACEMENT3D. Additionally, the directions for the axis and ref directions have been added to avoid any undefined references.
Given the error description, GPT corrected the schema and described its reasoning.
The model – although simple – is complete. The schema is valid, with proper spatial hierarchy and geometry. The model can be opened with no validation issues in the viewer. Well, it concludes the experiment.
The experiment conclusions (but not yet the end)
After the initial prompt and one additional iteration, the model is complete. Surely, the generated model is simple: it has a basic spatial hierarchy and geometry and doesn’t have additional meta-data (e.g., materials, and properties). Also, there are flaws like entity duplication (#7 and #42 are both IFCAXIS2PLACEMENT3D(#15, $, $);) Nonetheless, GPT was able to generate the model with just one correction, based solely on the validation output, with no expert guidance. This means the whole pipeline (initial prompt -> validation -> correction -> … -> proper output) can be automated.
- Did GPT create a valid IFC model at once, with the first prompt?
No. Although the spatial hierarchy and geometry were valid, there was an issue with a missing reference. - Did GPT create a valid IFC schema?
Yes. The second iteration brought the model with a valid schema (no errors when opening the model). - Did GPT create a complete model?
Yes. The second-iteration model was not only valid but also complete (in its simple form).
Seems ChatGPT4o with one-shot learning has the IFC potential.
So, although the core experiment is concluded, let’s examine further its capabilities.
Iteration #3 – clearing
Me:
The schema is correct and there are no issues when opening it in the viewer. Can you clear it now (remove unnecessary entities and duplications)?
ChatGPT:
Certainly! Here is a streamlined version of the IFC schema, with unnecessary entities and duplications removed:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_column.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Column model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Column Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
/* Building and location */
#20 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #21, $, $, .ELEMENT., $, $, $);
#21 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#20));
/* Column definition */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#21, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCRECTANGLEPROFILEDEF(.AREA., 'Square Profile', $, 300., 300.);
/* Spatial structure relation */
#60 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Column in Building', $, (#40), #20);
ENDSEC;
END-ISO-10303-21;
This version retains only the necessary entities and references, making the schema more concise.
GPT spotted and removed unused IFCDIRECTIONs (#16 and #17), but it did not handle the main flaw – duplicated IFCAXIS2PLACEMENT3D (#7 and #42). Not a success.
Iteration #4 – editing column’s profile
Me:
The schema is still correct. Now, change the column profile to a circle.
ChatGPT:
Sure! Here is the revised IFC schema with the column profile changed to a circle:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_column.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Column model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Column Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
/* Building and location */
#20 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #21, $, $, .ELEMENT., $, $, $);
#21 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#20));
/* Column definition */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#21, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
/* Spatial structure relation */
#60 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Column in Building', $, (#40), #20);
ENDSEC;
END-ISO-10303-21;
In this version, the IFCRECTANGLEPROFILEDEF has been replaced with IFCCIRCLEPROFILEDEF for a circular column profile with a radius of 150 mm (0.15 meters).
Success, also in terms of dimensions (from a square of 0.3 m width to a circle of radius 0.15 m).
Iteration #5 – additional column and a beam
Me:
Add a second column, 2 meters from the current one. Then, add a rectangular beam (width: 20 cm, height: 0.4m) supported by the columns.
ChatGPT:
Here's the updated IFC schema with a second column added 2 meters from the first one and a rectangular beam supported by the columns:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_structure.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Structure model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Structure Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCCARTESIANPOINT((2000.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
/* Building and location */
#20 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #21, $, $, .ELEMENT., $, $, $);
#21 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#20));
/* Column definitions */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column 1', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#21, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
#60 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO3', $, 'Concrete Column 2', $, $, #61, #62, $, $);
#61 = IFCLOCALPLACEMENT(#21, #63);
#62 = IFCPRODUCTDEFINITIONSHAPE($, $, (#64));
#63 = IFCAXIS2PLACEMENT3D(#16, $, $);
#64 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#65));
#65 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
/* Beam definition */
#70 = IFCBEAM('3xMto0vcH8Px8sbZlwlgO4', $, 'Concrete Beam', $, $, #71, #72, $, $);
#71 = IFCLOCALPLACEMENT(#21, #73);
#72 = IFCPRODUCTDEFINITIONSHAPE($, $, (#74));
#73 = IFCAXIS2PLACEMENT3D(#15, $, $);
#74 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#75));
#75 = IFCEXTRUDEDAREASOLID(#76, $, #18, 2000.);
#76 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 200., 400.);
/* Spatial structure relation */
#80 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Elements in Building', $, (#40, #60, #70), #20);
ENDSEC;
END-ISO-10303-21;
This updated IFC schema includes a second column located 2 meters away from the first one and a rectangular beam with a width of 200 mm and a height of 400 mm, supported by both columns.
It is a slightly more complex task. GPT did well with the second column and the spatial hierarchy. However, the beam geometry is not properly defined.
Iteration #6
Me:
Schema is correct. However, the beam is not supported by columns - it is aligned with the first column. Therefore, the beam is vertical, not horizontal.
ChatGPT:
I understand the issue. I'll adjust the placement of the beam so that it spans horizontally between the two columns, making it supported by both columns.
Here's the corrected IFC schema:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_structure.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Structure model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Structure Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCCARTESIANPOINT((2000.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
#19 = IFCDIRECTION((1.,0.,0.));
/* Building and location */
#20 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #21, $, $, .ELEMENT., $, $, $);
#21 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#20));
/* Column definitions */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column 1', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#21, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
#60 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO3', $, 'Concrete Column 2', $, $, #61, #62, $, $);
#61 = IFCLOCALPLACEMENT(#21, #63);
#62 = IFCPRODUCTDEFINITIONSHAPE($, $, (#64));
#63 = IFCAXIS2PLACEMENT3D(#16, $, $);
#64 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#65));
#65 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
/* Beam definition */
#70 = IFCBEAM('3xMto0vcH8Px8sbZlwlgO4', $, 'Concrete Beam', $, $, #71, #72, $, $);
#71 = IFCLOCALPLACEMENT(#21, #73);
#72 = IFCPRODUCTDEFINITIONSHAPE($, $, (#74));
#73 = IFCAXIS2PLACEMENT3D(#15, $, #19);
#74 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#75));
#75 = IFCEXTRUDEDAREASOLID(#76, $, #18, 2000.);
#76 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 200., 400.);
/* Spatial structure relation */
#80 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Elements in Building', $, (#40, #60, #70), #20);
ENDSEC;
END-ISO-10303-21;
In this updated schema, the beam (#70) is placed horizontally between the two columns by setting its local placement (#73) to be along the x-axis (#19 direction), ensuring it spans horizontally from the first column to the second column.
No improvement – the beam is still vertical.
Let’s give GPT another chance, with a bit more insightful hint.
Iteration #7
Me:
The issue is still not resolved. The beam is still extruded along the Z-axis, so it is vertical, not horizontal.
ChatGPT:
I understand the issue now. We need to ensure that the beam is extruded along the X-axis to be horizontal between the two columns. Here is the corrected IFC schema:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_structure.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Structure model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Structure Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCCARTESIANPOINT((2000.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
#19 = IFCDIRECTION((1.,0.,0.));
#20 = IFCDIRECTION((0.,1.,0.));
/* Building and location */
#21 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #22, $, $, .ELEMENT., $, $, $);
#22 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#21));
/* Column definitions */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column 1', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#22, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
#60 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO3', $, 'Concrete Column 2', $, $, #61, #62, $, $);
#61 = IFCLOCALPLACEMENT(#22, #63);
#62 = IFCPRODUCTDEFINITIONSHAPE($, $, (#64));
#63 = IFCAXIS2PLACEMENT3D(#16, $, $);
#64 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#65));
#65 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
/* Beam definition */
#70 = IFCBEAM('3xMto0vcH8Px8sbZlwlgO4', $, 'Concrete Beam', $, $, #71, #72, $, $);
#71 = IFCLOCALPLACEMENT(#22, #73);
#72 = IFCPRODUCTDEFINITIONSHAPE($, $, (#74));
#73 = IFCAXIS2PLACEMENT3D(#15, $, #18);
#74 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#75));
#75 = IFCEXTRUDEDAREASOLID(#76, $, #19, 2000.);
#76 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 200., 400.);
/* Spatial structure relation */
#80 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Elements in Building', $, (#40, #60, #70), #21);
ENDSEC;
END-ISO-10303-21;
In this corrected version, the beam (#70) is extruded along the X-axis (#19 direction) to span horizontally between the two columns. The placement of the beam is aligned with the first column and oriented to extend towards the second column, ensuring it is supported by both columns horizontally.
Limited success; one step closer.
Iteration #8
Me:
Now, the beam is horizontal but is located below the columns, not on them.
ChatGPT:
To correctly place the beam on top of the columns, we need to adjust the local placement of the beam so that it is positioned at the top of the columns. The top of the columns is at 2 meters above the base. We need to set the beam's placement accordingly.
Here is the revised IFC schema:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_structure.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Structure model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Structure Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCCARTESIANPOINT((2000.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
#19 = IFCDIRECTION((1.,0.,0.));
/* Building and location */
#21 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #22, $, $, .ELEMENT., $, $, $);
#22 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#21));
/* Column definitions */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column 1', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#22, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
#60 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO3', $, 'Concrete Column 2', $, $, #61, #62, $, $);
#61 = IFCLOCALPLACEMENT(#22, #63);
#62 = IFCPRODUCTDEFINITIONSHAPE($, $, (#64));
#63 = IFCAXIS2PLACEMENT3D(#16, $, $);
#64 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#65));
#65 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
/* Beam definition */
#70 = IFCBEAM('3xMto0vcH8Px8sbZlwlgO4', $, 'Concrete Beam', $, $, #71, #72, $, $);
#71 = IFCLOCALPLACEMENT(#22, #73);
#72 = IFCPRODUCTDEFINITIONSHAPE($, $, (#74));
#73 = IFCAXIS2PLACEMENT3D(#74, $, $);
#74 = IFCCARTESIANPOINT((0.,0.,2000.));
#75 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#76));
#76 = IFCEXTRUDEDAREASOLID(#77, $, #19, 2000.);
#77 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 200., 400.);
/* Spatial structure relation */
#80 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Elements in Building', $, (#40, #60, #70), #21);
ENDSEC;
END-ISO-10303-21;
In this corrected version, the beam's local placement (#74) is set to 2 meters above the base point (0,0,2000) to align it with the tops of the columns. The beam is then extruded along the X-axis (#19 direction) to span horizontally between the two columns, ensuring it is supported correctly.
This iteration brought an error thrown by the viewer validation. IFCPRODUCTDEFINITIONSHAPE (#72) shouldn’t reference IFCCARTESIANPOINT (#74) but a IFCSHAPEREPRESENTATION.
Iteration #9
Me:
ERROR Xbim.IO.Step21.XbimP21Parser
Entity #72 IFCPRODUCTDEFINITIONSHAPE, error at parameter 3-Representations value = #74=IFCCARTESIANPOINT
ChatGPT:
I see the mistake. The error is caused by incorrectly using an IFCCARTESIANPOINT where an IFCSHAPEREPRESENTATION should be. Let's correct the placement and representation of the beam properly.
Here's the revised schema:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_structure.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Structure model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Structure Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCCARTESIANPOINT((2000.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
#19 = IFCDIRECTION((1.,0.,0.));
#20 = IFCCARTESIANPOINT((0.,0.,2000.));
/* Building and location */
#21 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #22, $, $, .ELEMENT., $, $, $);
#22 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#21));
/* Column definitions */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column 1', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#22, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
#60 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO3', $, 'Concrete Column 2', $, $, #61, #62, $, $);
#61 = IFCLOCALPLACEMENT(#22, #63);
#62 = IFCPRODUCTDEFINITIONSHAPE($, $, (#64));
#63 = IFCAXIS2PLACEMENT3D(#16, $, $);
#64 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#65));
#65 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
/* Beam definition */
#70 = IFCBEAM('3xMto0vcH8Px8sbZlwlgO4', $, 'Concrete Beam', $, $, #71, #72, $, $);
#71 = IFCLOCALPLACEMENT(#22, #73);
#72 = IFCPRODUCTDEFINITIONSHAPE($, $, (#75));
#73 = IFCAXIS2PLACEMENT3D(#20, $, $);
#75 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#76));
#76 = IFCEXTRUDEDAREASOLID(#77, $, #19, 2000.);
#77 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 200., 400.);
/* Spatial structure relation */
#80 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Elements in Building', $, (#40, #60, #70), #21);
ENDSEC;
END-ISO-10303-21;
In this updated schema, the beam's local placement is corrected so it is positioned at 2 meters above the base (#20 representing the point (0,0,2000)). The beam is extruded along the X-axis (#19 direction) to span horizontally between the two columns. This ensures the beam is properly supported by both columns.
GPT was able to correct the error and also place the beam on the columns. However, the beam’s profile is not proper – it is “flat”.
Iteration #10
Me:
The beam is positioned correctly. However, its profile is flat - it does not have height.
ChatGPT:
To ensure the beam has the correct height, we need to adjust the profile definition and extrusion direction appropriately. Here is the corrected IFC schema to include a properly defined beam profile with height:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_structure.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Structure model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Structure Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCCARTESIANPOINT((2000.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
#19 = IFCDIRECTION((1.,0.,0.));
#20 = IFCCARTESIANPOINT((0.,0.,2000.));
#21 = IFCDIRECTION((0.,1.,0.));
/* Building and location */
#22 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #23, $, $, .ELEMENT., $, $, $);
#23 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#22));
/* Column definitions */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column 1', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#23, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
#60 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO3', $, 'Concrete Column 2', $, $, #61, #62, $, $);
#61 = IFCLOCALPLACEMENT(#23, #63);
#62 = IFCPRODUCTDEFINITIONSHAPE($, $, (#64));
#63 = IFCAXIS2PLACEMENT3D(#16, $, $);
#64 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#65));
#65 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
/* Beam definition */
#70 = IFCBEAM('3xMto0vcH8Px8sbZlwlgO4', $, 'Concrete Beam', $, $, #71, #72, $, $);
#71 = IFCLOCALPLACEMENT(#23, #73);
#72 = IFCPRODUCTDEFINITIONSHAPE($, $, (#75));
#73 = IFCAXIS2PLACEMENT3D(#20, $, $);
#75 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#76));
#76 = IFCEXTRUDEDAREASOLID(#77, $, #19, 2000.);
#77 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 200., 400.);
/* Spatial structure relation */
#80 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Elements in Building', $, (#40, #60, #70), #22);
ENDSEC;
END-ISO-10303-21;
In this corrected version, the beam's profile is defined with both width and height, ensuring it has the correct dimensions. The beam is placed at 2 meters above the base, and it spans horizontally between the two columns, ensuring proper support and alignment.
Still no improvement. The next prompt will contain more insightful guidance and a fragment of the IFC documentation (however, copied “as is”, with no special highlights – the whole content from the IFCEXTRUDEDAREASOLID documentation).
Iteration #11
Me:
There is an issue with the beam extrusion. Below is a documentation for an entity that might help resolve the problem.
8.8.3.15 IfcExtrudedAreaSolid
[... rest of the IfcExtrudedAreaSolid documentation]
ChatGPT:
To ensure the beam has the correct height and is extruded properly along the X-axis, I'll ensure the IfcExtrudedAreaSolid entity is correctly defined. Here’s the updated IFC schema with the beam extruded correctly:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_structure.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Structure model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Structure Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCCARTESIANPOINT((2000.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
#19 = IFCDIRECTION((1.,0.,0.));
#20 = IFCCARTESIANPOINT((0.,0.,2000.));
/* Building and location */
#21 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #22, $, $, .ELEMENT., $, $, $);
#22 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#21));
/* Column definitions */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column 1', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#22, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
#60 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO3', $, 'Concrete Column 2', $, $, #61, #62, $, $);
#61 = IFCLOCALPLACEMENT(#22, #63);
#62 = IFCPRODUCTDEFINITIONSHAPE($, $, (#64));
#63 = IFCAXIS2PLACEMENT3D(#16, $, $);
#64 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#65));
#65 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
/* Beam definition */
#70 = IFCBEAM('3xMto0vcH8Px8sbZlwlgO4', $, 'Concrete Beam', $, $, #71, #72, $, $);
#71 = IFCLOCALPLACEMENT(#22, #73);
#72 = IFCPRODUCTDEFINITIONSHAPE($, $, (#75));
#73 = IFCAXIS2PLACEMENT3D(#20, $, $);
#75 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#76));
#76 = IFCEXTRUDEDAREASOLID(#77, $, #19, 2000.);
#77 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 400., 200.); /* Correcting dimensions here */
/* Spatial structure relation */
#80 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Elements in Building', $, (#40, #60, #70), #21);
ENDSEC;
END-ISO-10303-21;
In this schema:
#77 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 400., 200.); defines the beam profile with a width of 400mm and a height of 200mm.
The extrusion direction #76 = IFCEXTRUDEDAREASOLID(#77, $, #19, 2000.); correctly uses #19 to ensure the beam is extruded along the X-axis.
This ensures the beam has the correct height and width, and it is positioned horizontally between the columns.
It didn’t help. The next prompt will contain more guidance and a relevant fragment from the documentation.
Iteration #12
Me:
The issue is still not resolved. The problem is here:
#76 = IFCEXTRUDEDAREASOLID(#77, $, #19, 2000.);
The second argument in the current schema is omitted with "$". However, it can help resolve the flat profile issue.
This is the documentation fragment describing this argument:
2 Position OPTIONAL IfcAxis2Placement3D
Position coordinate system for the resulting swept solid of the sweeping operation. The position coordinate system allows for re-positioning of the swept solid. If not provided, the swept solid remains within the position as determined by the cross section or by the directrix used for the sweeping operation.
ChatGPT:
Thanks for pointing out the issue with the missing position argument. I will update the schema to include the Position argument in the IfcExtrudedAreaSolid definition for the beam.
Here’s the revised schema:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_structure.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Structure model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Structure Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCCARTESIANPOINT((2000.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
#19 = IFCDIRECTION((1.,0.,0.));
#20 = IFCCARTESIANPOINT((0.,0.,2000.));
#21 = IFCAXIS2PLACEMENT3D(#15, #18, #19); /* Position with Z direction upwards and X direction along the beam */
/* Building and location */
#22 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #23, $, $, .ELEMENT., $, $, $);
#23 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#22));
/* Column definitions */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column 1', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#23, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
#60 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO3', $, 'Concrete Column 2', $, $, #61, #62, $, $);
#61 = IFCLOCALPLACEMENT(#23, #63);
#62 = IFCPRODUCTDEFINITIONSHAPE($, $, (#64));
#63 = IFCAXIS2PLACEMENT3D(#16, $, $);
#64 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#65));
#65 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
/* Beam definition */
#70 = IFCBEAM('3xMto0vcH8Px8sbZlwlgO4', $, 'Concrete Beam', $, $, #71, #72, $, $);
#71 = IFCLOCALPLACEMENT(#23, #73);
#72 = IFCPRODUCTDEFINITIONSHAPE($, $, (#75));
#73 = IFCAXIS2PLACEMENT3D(#20, $, $);
#75 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#76));
#76 = IFCEXTRUDEDAREASOLID(#77, #21, #19, 2000.); /* Correcting to include the position */
#77 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 400., 200.); /* Correcting dimensions here */
/* Spatial structure relation */
#80 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Elements in Building', $, (#40, #60, #70), #22);
ENDSEC;
END-ISO-10303-21;
In this corrected schema:
The IfcExtrudedAreaSolid for the beam (#76) now includes a proper position (#21), which ensures the correct orientation and height.
The dimensions for the beam profile are properly set in #77 with a width of 400mm and a height of 200mm.
The IfcAxis2Placement3D (#21) is defined to position and orient the beam correctly within the model space.
This should ensure that the beam has the correct height and is extruded properly along the X-axis while being positioned correctly on top of the columns.
Neither this attempt was successful.
The last try, with more guidance:
Iteration #13
Me:
The schema is correct, but the beam section is still flat. I think there is an issue with #21 = IFCAXIS2PLACEMENT3D(#20, #18, #19);. Are you sure the axes are correct?
ChatGPT:
I see the issue now. The local placement of the beam's profile may not be correctly oriented. Let's make sure the IfcAxis2Placement3D is correctly defining the placement and orientation of the beam's profile. Specifically, the X and Y directions should be correctly aligned.
Here's the updated IFC schema with the corrected axes for the beam's profile placement:ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
( 'ViewDefinition [ReferenceView_V1-2]',
'Comment [manual creation of example file]'
),
'2;1');
FILE_NAME(
'simple_structure.ifc',
'2024-06-03T00:00:00',
('Your Name'),
('Your Organization'),
'IFC text editor',
'IFC text editor',
'Structure model created for example');
FILE_SCHEMA(('IFC4'));
ENDSEC;
DATA;
/* Project context and header information */
#1 = IFCPROJECT('0nGbkyXJ5D00000Abv$kVQ', #2, 'Simple Structure Project', $, $, $, $, (#6), #10);
#2 = IFCOWNERHISTORY(#3, #5, $, .ADDED., 1234567890, $, $, 1234567890);
#3 = IFCPERSONANDORGANIZATION(#4, #8, $);
#4 = IFCPERSON($, 'Name', 'Your', $, $, $, $, $);
#5 = IFCAPPLICATION(#8, '1.0', 'IFC text editor', 'ifcTE');
#6 = IFCGEOMETRICREPRESENTATIONCONTEXT($, 'Model', 3, 1.0E-5, #7, $);
#7 = IFCAXIS2PLACEMENT3D(#15, $, $);
#8 = IFCORGANIZATION($, 'Your Organization', $, $, $);
#10 = IFCUNITASSIGNMENT((#11, #12));
#11 = IFCSIUNIT(*, .LENGTHUNIT., .MILLI., .METRE.);
#12 = IFCSIUNIT(*, .PLANEANGLEUNIT., $, .RADIAN.);
/* Coordinates and directions */
#15 = IFCCARTESIANPOINT((0.,0.,0.));
#16 = IFCCARTESIANPOINT((2000.,0.,0.));
#18 = IFCDIRECTION((0.,0.,1.));
#19 = IFCDIRECTION((1.,0.,0.));
#20 = IFCCARTESIANPOINT((0.,0.,2000.));
#21 = IFCDIRECTION((0.,1.,0.)); /* Corrected direction for Y-axis */
#22 = IFCAXIS2PLACEMENT3D(#15, #18, #21); /* Corrected axis placement for beam profile */
/* Building and location */
#23 = IFCBUILDING('1L4fF0YKnD_QuF03m9zv4x', $, 'Simple Building', $, $, #24, $, $, .ELEMENT., $, $, $);
#24 = IFCLOCALPLACEMENT($, #7);
#30 = IFCRELAGGREGATES('2Lw2JztX19bh8A0Ucm9t7N', $, $, $, (#1), (#23));
/* Column definitions */
#40 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO2', $, 'Concrete Column 1', $, $, #41, #50, $, $);
#41 = IFCLOCALPLACEMENT(#24, #42);
#42 = IFCAXIS2PLACEMENT3D(#15, $, $);
#50 = IFCPRODUCTDEFINITIONSHAPE($, $, (#51));
#51 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#52));
#52 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
#53 = IFCCIRCLEPROFILEDEF(.AREA., 'Circular Profile', $, 150.);
#60 = IFCCOLUMN('3xMto0vcH8Px8sbZlwlgO3', $, 'Concrete Column 2', $, $, #61, #62, $, $);
#61 = IFCLOCALPLACEMENT(#24, #63);
#62 = IFCPRODUCTDEFINITIONSHAPE($, $, (#64));
#63 = IFCAXIS2PLACEMENT3D(#16, $, $);
#64 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#65));
#65 = IFCEXTRUDEDAREASOLID(#53, $, #18, 2000.);
/* Beam definition */
#70 = IFCBEAM('3xMto0vcH8Px8sbZlwlgO4', $, 'Concrete Beam', $, $, #71, #72, $, $);
#71 = IFCLOCALPLACEMENT(#24, #73);
#72 = IFCPRODUCTDEFINITIONSHAPE($, $, (#75));
#73 = IFCAXIS2PLACEMENT3D(#20, $, $);
#75 = IFCSHAPEREPRESENTATION(#6, 'Body', 'SweptSolid', (#76));
#76 = IFCEXTRUDEDAREASOLID(#77, #22, #19, 2000.); /* Correcting to include the position */
#77 = IFCRECTANGLEPROFILEDEF(.AREA., 'Rectangular Profile', $, 400., 200.); /* Correcting dimensions here */
/* Spatial structure relation */
#80 = IFCRELCONTAINEDINSPATIALSTRUCTURE('5ZbkTVuNX2ge9mB3c$h9V6', $, 'Elements in Building', $, (#40, #60, #70), #23);
ENDSEC;
END-ISO-10303-21;
In this corrected schema:
The IfcAxis2Placement3D for the beam's profile placement (#22) now has the correct direction for the Y-axis (#21), ensuring the profile is oriented correctly.
The profile of the beam (#77) is now properly placed and extruded along the X-axis with the correct dimensions (400mm width and 200mm height).
This should ensure that the beam has the correct height and is extruded properly along the X-axis while being positioned correctly on top of the columns.
There is a change in the beam, but not the expected one.
At this point, I think it is reasonable to conclude that this task was too complex for GPT. However, the resolution was not far away:
We have to edit: 76 = IFCEXTRUDEDAREASOLID(#77, #22, #19, 2000.);
To:76 = IFCEXTRUDEDAREASOLID(#77, #22, #18, 2000.);
To first have a proper volumetric beam of our cross-section.
And then we have to edit:22 = IFCAXIS2PLACEMENT3D(#15, #18, #21);
To:22 = IFCAXIS2PLACEMENT3D(#15, #19, #18);
To rotate the beam.
The end (of this round)
The main goal of this post was to test ChatGPT4o’s ability to generate IFC models with a prompt engineering technique called one-shot learning. As already concluded, it did really well – after the initial prompt and one additional iteration, the model had a valid schema and was complete. Although our example is just a simple model, I think this is impressive. GPT is a general-purpose model, but its internal knowledge and the ability to in-context learning (getting knowledge from a valid IFC schema example provided in the first prompt) enabled it to achieve the experiment goal.
Encouraged by the success, I further examined the GPT4o IFC abilities. The results are mixed.
- Task 1: Schema clearance
Partial success. GPT removed unusedIFCDIRECTIONsbut didn’t remove the main flaw, duplication ofIFCAXIS2PLACEMENT3D. - Task 2: Column cross-section change
Success. GPT correctly changed the column’s cross-section from square to circle, maintaining the dimensions. - Task 3: Additional column and beam
Partial success (?). After the first prompt, GPT correctly created an additional column. It also created a beam of proper cross-section, but it wasn’t correctly placed. In the next 8 iterations, GPT tried to refine the beam’s position with various outcomes, but not the completely proper one.
What I liked is that the IFC schema was valid through almost all iterations. And I think there is still a field for improvement. Developing Large Language Models’ systems or even the “chatting pipelines” is an engineering task itself. Maybe with few-shot learning (more valid IFC schemas examples) or other prompt engineering techniques, GPT would perform better? Anyway, the potential is here.
