2D drawing artefacts in ifc file

G by GBWbim on 4 Mar 2025, edited 10 Mar 2025 #

I have just tried to create 2d drawings from within an ifc file using Blender 4.3.2 and Bonsai 0.8.1 (with limited success but did manage a floor plan and "elevation" in section) and to check, subsequently opened the corresponding file in the ifcopenshell pipeline viewer online where strange volumes have suddenly appeared in the model. These are also visible in other ifc viewers although not in Solibri Anyway. I am clearly not doing this correctly, so is there a definitive workflow to avoid this? Respective images attached:

A by Ace on 4 Mar 2025 #

Is it possible to share the IFC file?

Or a paired down version that just has the problem elements?

G by GBWbim on 5 Mar 2025, edited 5 Mar 2025 #

Hi Ace, thanks for the response. I have deleted much of the geometry, but the artefacts are still visible in the openifc viewer; there should be 11 drawings still. I hope this helps. Here is the zipped ifc file.

A by Ace on 5 Mar 2025 #

Hi @GBWbim I'm not sure if you attached the ifc I can't see it under your comment

Z by zoomer on 5 Mar 2025 #

@Ace said:

Hi @GBWbim I'm not sure if you attached the ifc I can't see it under your comment

I see a "missing image" icon at the bottom - when hovering, RMB click, save Image as .... it will download a zip file, which contains the IFC .....

J by JanF on 5 Mar 2025 #

@Ace said:

Hi @GBWbim I'm not sure if you attached the ifc I can't see it under your comment

Should be visible now.

A by Ace on 6 Mar 2025 #

Hi GBWbim,

In your paired down file I can't see the artefacts in Open Ifc VIewer, Bonsai or Freecad:

I think perhaps you removed the issue? Perhaps try reprinting all your SVGs and seeing again if the issue persists

G by GBWbim on 6 Mar 2025 #

Hi Ace,

strange; in my open ifc viewer 25.12 they are still visible as previously posted. Perhaps there is something missing in my system? As you suggest, I will go back to the original file and start again. How do I adjust the location of the elevations and sections. The defaults (west/east/north/south etc) do not produce a drawing.

J by JanF on 6 Mar 2025, edited 6 Mar 2025 # +2 votes

BIMCollab Zoom 8.2.2 also shows these elements:

They are the annotations Bonsai uses as placeholder for the view information, so no, there is no workaround for this (apart from deleting your plans and elevations).

As far as I remember, they should not be shown in the model view according to the spec, so this is a problem of the IFC viewer and not something Bonsai can fix.

G by GBWbim on 7 Mar 2025 # +1 votes

Hi JanF, thanks for confirming.

In the ifcopenshell pipeline viewer itself, they are also still visible and my guess was indeed that from their form, the blocks represented 4 section boxes for elevations/sections and a number of floor plans at respective levels: So for "ifc conformance", these would have to be deleted? Their positions relative to the model perhaps helps to explain why some do not produce correct drawings, but I can't find the data to adjust their position in the bonsai gui.

J by JanF on 7 Mar 2025, edited 7 Mar 2025 # +1 votes

No, you don't have to delete anything. The objects are a part of a valid ifc file, the viewer is just supposed to hide them (same as openings for example).

The pyramid is your 3D view, you can activate it, go to the N panel, View, lock camera to View and then pan or orbit:

For sections and elevations you can activate the view and orbit without locking the camera, you'll see the camera in front of you as an object and can move or rotate it around:

Generally speaking you can always find any camera in the outliner and move it around:

G by GBWbim on 7 Mar 2025 #

Thanks for tips, just getting the hang of it. I see that the "drawings" only appear in the tree view once activated and can be manipulated. I tried switching their visibility in the viewport, disabling in renders and excluding from view layer in the hope this might disable them from being viewed in the external viewers (including ifcopenshell pipeline itself - disappointing) but confirm they still can. Since I want to display the model online (in an apparently non-conformant viewer) for a uni presentation, it seems I really do have to delete them again - boo. Any further recommendations would be welcome. I now wish to delete the uploaded model from the forum.

J by JanF on 8 Mar 2025 #

Can you not delete the comment where you posted it? Next time please send private stuff privately.

Regarding the viewer, for ifcopenshell I'd suggest you file a bug, you might get it gixed quite quickly.

G by GBWbim on 10 Mar 2025 #

@GBWbim said:

Hi Ace, thanks for the response. I have deleted much of the geometry, but the artefacts are still visible in the openifc viewer; there should be 11 drawings still. I hope this helps. Here was the zipped ifc file.