Integration of BlenderBIM Features : FreeCAD Arch/BIM - Native IFC

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proghettolab
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by proghettolab »

A problem I encountered with IFC objects was while printing with TechDraw. IFC objects, from the simple table to the more complex sink, appear with triangles and the triangles are printed, so you are forced to "clean" with Inkscape.
With this premise, IFC files are more useful if you render with Blender and not if you have to get technical drawing with FreeCAD.
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thomas-neemann
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by thomas-neemann »

proghettolab wrote: Thu Oct 06, 2022 8:44 pm ...
in my opinion there is no reason to import ifc objects into a construction. ifc is intended for reference, not as a data exchange format
Gruß Dipl.-Ing. (FH) Thomas Neemann

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yorik
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by yorik »

paullee wrote: Thu Oct 06, 2022 7:56 pm Possible to start with something simple as a wall, or something not exist in FreeCAD Arch/BIM (any?) as a test / showcase; then the community can extend to other objects?
That's actually a very good idea! I'll have a look at how that could work.
proghettolab wrote: Thu Oct 06, 2022 8:44 pm A problem I encountered with IFC objects was while printing with TechDraw. IFC objects, from the simple table to the more complex sink, appear with triangles and the triangles are printed, so you are forced to "clean" with Inkscape.
That's not a problem of IFC itself, but how people (and specially websites like bimobjects.com) use IFC. The IFC format can contain very good Brep and solid-based geometry (like we use in FreeCAD), but also mesh (triangulated) geometry. Most websites generate their geometry with proprietary tools like Revit, then convert that to IFC. The process they use apparently triangulate everything (which is also what Revit does with complicated geometry). They basically don't care much of producing good quality IFC files, unfortunately.

A good place to obtain quality models is https://grabcad.com/library?page=1&time ... slash-iges (Step files are usually of pretty good quality, as IFC should be... :roll: )
paullee
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by paullee »

Thanks Yorik :)
sire42
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by sire42 »

Interesting discussion.

Sounds to me like a quality score of IFC models would be useful.
It shall value high information content (parametric ifc object) over low information content (mesh geometry).

Losing information to the void is easy, but (re)gaining it requires external qualified input (like: "This mesh appears to be a wall, I'll attribute it like this" repeat...).

So if FreeCAD import/exports an IFC, but the score does not change, fine; it's just a kind of normalisation (from ArchBIM perspective).
If BlenderBIM does not touch the IFC, of course it will keep it's information content score.

Note I discuss a similar problem about hatching pattern for TechDraw (https://forum.freecadweb.org/viewtopic. ... 10#p631941).
The PAT file format actually is a high information content format (corresponds to parametric geometry) compared to bitmap (corresponds to voxels).
An SVG pattern element is of higher information content than an SVG Basic/Tiny.
And especially SVG here seems to be quite comparable to the IFC: One embracing name (IFC, SVG) actually contains all kind of modelling approaches so that implementers start to strip down, not support all, eventually to end up with the smallest common compromise: low information content that can be easily shown on screen, but never be modified in a semantic way it once was meant to be (not to speak about structural or energy analyses).

Bottom line: Maybe it's not about another exporter/importer/workbench, but a common IFC approach (between the champion FOSS) to focus the high information content IFC objects even if this means, fancy flower pots based on Blender created mesh geometry cannot be exchanged?
martin15135215
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by martin15135215 »

It would be nice, when FreeCAD also will have Native IFC support like described in this article https://osarch.org/2022/10/15/whitepaper-published-on-native-ifc-methodologies/.
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by Moult »

For those reading along, just want to clarify that the BlenderBIM Add-on code base is split into two sections: Blender UI, and IFC core. This means that it doesn't matter about meshes vs solids, you want to edit IFC directly or feed it "generated" data from another engine, etc. You can choose yourself where you decide to sit best in the spectrum between "FreeCAD/Blender/etc is the data source" as one extreme and "IFC is the data source" at another extreme. FreeCAD is currently at the former extreme, the BlenderBIM Add-on is currently more at the latter extreme (though started at the former). The IFC core is what we're talking about here, which can in theory be fully reused in FreeCAD to make FreeCAD a native IFC authoring platform.

Also keep in mind that native IFC authoring is not mutually exclusive with custom modeling / parametric strategies / data generation engines. You can have both. IFC is an ISO standard, and so it naturally will only contain the most common denominators in our industry, simple things like basic layered extrusion, the concept that walls can have fire ratings, etc. An ISO standard will never dictate how the FreeCAD ACME Stair Generator 2.0 will work, as it's out of scope of ISO :) So for example, even though the BlenderBIM Add-on is 100% native IFC, we can still develop things like window / door / stair generators, use OpenSCAD for constraint based profile editing via CADSketcher, use IfcSverchok for visual node programming, etc.

I'm very keen on seeing a prototype of this happen in FreeCAD, and would love to dedicate a week or two co-hacking with Yorik to see it happen :)
I also blog about 3D rendering, architecture, software and other on thinkMoult.com. RSS / Atom feed available for your convenience.
paullee
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by paullee »

The best news for the FreeCAD Arch and BlenderBIM community to have their founders to work together on a prototype :lol:

@Moult what do you expect how the 'native IFC editing' in FreeCAD would be different from BlenderBIM? Editing and UI response in BlenderBIM seems to be extremely fast !

The whitepaper @martin15135215 cross-posted is interesting; maybe potentially a demonstration FreeCAD Arch and BlenderBIM works together on a CDE ?
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Moult
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by Moult »

For things like editing attributes, properties, and non-geometric relationships (documents, actors, work schedules, etc) I see no difference. The difference should come in where FreeCAD has strengths that Blender doesn't. For example, FreeCAD has strengths in solid modeling, and so editing those types of geometry would be much more fluent in FreeCAD than in Blender, whose strength lies in mesh modeling. FreeCAD is also very good at fabrication, so integration with IFC's fabrication features like precast concrete, assembly scheduling, void features (milling, drilling, etc) would be much more natural than in Blender. FreeCAD also seems to have a built-in spreadsheet, which might be good for cost scheduling. FreeCAD's built-in structural integration might also make it better suited for structural modeling and setting up load cases. FreeCAD's tech draw might also provide much better IFC drafting compared to Blender, where we have to fight the Blender interface to make things work.
I also blog about 3D rendering, architecture, software and other on thinkMoult.com. RSS / Atom feed available for your convenience.
paullee
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Re: Integration of BlenderBIM Feaures : FreeCAD Arch/BIM

Post by paullee »

Thanks Moult for the detailed explanation :D
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