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GeometryGym / GeometryGymIFC

C# classes to generate and parse OpenBIM IFC files
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Modifying an existing entity #67

Open CJAndrew84 opened 1 year ago

CJAndrew84 commented 1 year ago

Hi,

I'm trying to modify an existing Brep (which is the inner face of a pipe).

Is there a way to simply "thicken" the Brep to add a wall thickness.

I've tried to extract the start and end xyz values and recreate but that didnt work either (to many points in the polyloop). Example of what happened when i tried to extract the points image

Existing IFC file in using IFC4.0 Schema (not sure how i can change this)

jmirtsch commented 1 year ago

I'm not aware of any tool to easily change thickness of thin walled geometry in a faceted/meshed state (aside perhaps from a most trivial case of a straight pipe). The semantics are lost. If it's difficult to change, it's also difficult to detect the thickness when receiving an IFC file in this state. Typically the wall thickness of the pipe would be nominated in a property set. Looks like the standard property is inner and outer diameter https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/lexical/Pset_PipeSegmentTypeCommon.htm
It should be trivial to change the wall thickness in the underlying model, but given you want to modify the IFC I'm assuming you don't have access to this.

CJAndrew84 commented 1 year ago

Going to extract all the data and recreate the pipe network using IFC 4x3 (Distribution Elements and Pipe Segments).

Source software (MicroDrainage) doesn't allow me to add wall thicknesses, and don't have the time to run all the networks through C3D or other tools.

Just trying to figure out how to do a sloping Circular hollow Shape that I can give to IfcPipeSegment.

I was thinking I could use IfcSectionedSolid, but have figured out how to add the slope.

jmirtsch commented 1 year ago

Thanks for the further info. I'm not familiar with MicroDrainage. Are they actively improving their IFC export? It might be they just need information on how to author better IFC. Or else if you have means to tag pipes with meta data representing wall thickness, the file might be post processed. Some sample IFC would help. You can send it privately if you can't upload to public (or the file is large).

CJAndrew84 commented 1 year ago

That would be Autodesk after their purchase of innovyze. Know anyone working with them on IFC exporters? Modifying the detail and adding extra Document Attributes (hosted on PW) through use of your library has allowed me to upgrade the IFC to 4x3 and re structure the data to align to National Highways ADMM structure for Drainage