Author Topic: IFC to DWG conversion  (Read 31587 times)

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lamarn

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IFC to DWG conversion
« on: September 04, 2019, 05:29:57 PM »
Strange thing happening to my solids (rebar model) after import using BricsCAD.
Color assignment does not seem to work in any way, .. only when i explode them into surfaces.
Here is a image of the complete work. The diameter of bars should have different colors. So yellow is 20 mm.
Attached a sample.

nb. Otherwise BricsCAD does a great job importing IFC!!

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MickD

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Re: IFC to DWG conversion
« Reply #1 on: September 04, 2019, 07:19:31 PM »
the short answer:
The biggest problem with IFC is that vendors often don't stick strictly to the schema when exporting their objects, they often just export the bare essentials of information rather than getting down into the nitty gritty of the schema.

For example, when importing a 3D solid universal beam ('H' beam), if the profile exported is described as "310UB40" and the application importing the schema uses a matching profile but describes it as "UB31040" you usually have to write a mapping file so it knows how to draw the beam.
That is, Bricscad can't draw missing info if it's not exported, each application uses the schema differently.

The longer version:
This is ridiculous!

The schema caters for the primitive profile geometry but it is too specific and it's a lot of work to create the geometry routines to cater for every type, have a dig around in here for an idea on the complexity that is IFC -> https://standards.buildingsmart.org/IFC/DEV/IFC4_2/FINAL/HTML/

That is at the profile level and it goes much deeper!

What they should have done is have very primitive geometries such as points, lines, polylines and compositions of these and use these to store the primitive geometry that any CAD platform draws easily. All other data is just that, data!
What this means is that any CAD platform can at the very least draw the 3d solid, it doesn't matter what it's called really as long as the rendered object is true.

BIM is a wonderful thing but it's a beast to implement using IFC. Until all vendors validate their data against the schema on export and import will the data be true and correct.

end rant :)


Then again, it may just be a bug, let BricsCAD know and they might be able to help. BricsCAD support is very helpful and usually get back very quickly considering.

Forth is like the Tao: it is a Way, and is realized when followed.
Its fragility is its strength; its simplicity is its direction - Michael Ham

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Greg B

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Re: IFC to DWG conversion
« Reply #2 on: September 05, 2019, 08:49:09 AM »
Then again, it may just be a bug, let BricsCAD know and they might be able to help. BricsCAD support is very helpful and usually get back very quickly considering.

"Then again, ..."


Pure genius Mick.


Pure genius.

lamarn

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Re: IFC to DWG conversion
« Reply #3 on: September 05, 2019, 05:31:18 PM »
Thanks for your views on this matter. I also think that this whole bimthing essencialy misses a decent CAD basis. But i am impressed how good and fast IFC is imported in BricsCAD. I will not compare this with the way Autodesk is handling in AutoCAD Architecture or even Revit. Just starting to compare these two would be a insult.

I informed the service desk but wanted to share it also.
Hope that BricsCAD can sort it out.
Color is important for understanding rebar models

« Last Edit: September 05, 2019, 05:50:32 PM by lamarn »
Design is something you should do with both hands. My 2d hand , my 3d hand ..

MickD

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Re: IFC to DWG conversion
« Reply #4 on: September 05, 2019, 06:52:30 PM »
Then again, it may just be a bug, let BricsCAD know and they might be able to help. BricsCAD support is very helpful and usually get back very quickly considering.

"Then again, ..."


Pure genius Mick.


Pure genius.

 :whistling:

Thanks for your views on this matter. I also think that this whole bim thing essencialy misses a decent CAD basis. But i am impressed how good and fast IFC is imported in BricsCAD. I will not compare this with the way Autodesk is handling in AutoCAD Architecture or even Revit. Just starting to compare these two would be a insult.

...


Yep, my first experience with BIM was trying to import a Revit ifc file into Tekla Structures, it was impossible without creating mapping files and other tweaks. I nearly gave up and modeled it from scratch.

BricsCAD takes BIM very seriously and I'm not surprised it's fast as they also take development and bug fixes very seriously.
Forth is like the Tao: it is a Way, and is realized when followed.
Its fragility is its strength; its simplicity is its direction - Michael Ham

"First, solve the problem. Then, write the code." John Johnson