IFC option "export links as separate models" causes wrong placement in Solibri

dg — Tue, 21 Apr 2020 10:36:10 GMT

Ok, so I need a real expert here I think, and I´ll try to be detailed.

I have a housing project, with 4 housetypes. Each type exists up to 30 times in the project, usually put together in rows af 6-8. Each type is modelled within it´s own Revit file. These 4 files does not contain a shared coordinate system, but has simply been modelled on top of a masterplan CAD file, showing the footprint of all house instances across all 4 types. This footprint file is a link (manual center), and has been placed in the same location, in each of the 4 type files, before any modeling took place. I randomly chose a "starting position" for each house type, within the allotted footprint types, meaning for example, that of the 30 footprints for house type A, I picked a random one, and modeled type A there. These 4 files were then linked (with origin2origin I believe), into an aggregate model, also containing the footprint file at the same location as the 4 type files. I used origin2origin here, because the original instance of the 4 typefiles would then be placed correctly within an allotted footprint, in the aggregate model. I then proceed to copy the 4 links onto all the footprints shown in the master CAD. Now, after having done this there were multiple changes to the placements of the links, meaning in a row of 6 type A houses, I might have deleted 5 of them, rotated and moved the last one to the new location (anywhere from 0,1 to 2 meters, and rotated maybe 1-2 degrees), and then copy it 5 more times to get the entire row of 6 in the new correct position.

Here is what´s happening to me, that I don´t understand. When I export the aggregated model to IFC using the "Export linked files as separate IFC" option, and then open all 60+ ifc files in Solibri model viever, all the links seems to be placed correct, except for the 4 originally placed instances of each house type. So, it seems that these 4 instances are somehow exported in an earlier position, than the rest.

Bonus info. The master CAD file contains the projects shared coordinates. I believe, that after copying the links, creating the first version of the aggregated model, I then acquired those coordinates (not in the 4 type files, only in the aggregated model). I then later proceeded to move/delete/copy the links again to their new position (I did not re-link the type files, only move/copy or delete them). In my own understanding of shared sites/coordinates this should not cause problems.

Can anyone explain what is happening here? I have attached an image of the aggregated IFC model to show how the original linked type A and B houses a placed wrong. The original linked type C and D are also displaced, but it´s not visible as they are not in rows. Also attached my IFC export settings.

Things I tried: unchecking "include IFC site", just because.

Re: IFC option "export links as separate models" causes wrong placemen

Rafal.Gaweda — Tue, 05 May 2020 08:29:11 GMT

Hi @dg

I am afraid without files it will be hard to investigate.

Check the same in Navisworks.

If it is not correct It would be good to send me or post all revit files You use in project.

Re: IFC option "export links as separate models" causes wrong placemen

Rafal.Gaweda — Tue, 05 May 2020 15:24:35 GMT

Hi @dg

Thanks for the files.

I have escalated this issue to dvlp team for further investigation.

I will update You asap.

Thank You for Your patience.

topic IFC option "export links as separate models" causes wrong placement in Solibri in Revit Architecture Forum

IFC option "export links as separate models" causes wrong placement in Solibri

Re: IFC option "export links as separate models" causes wrong placemen

Re: IFC option "export links as separate models" causes wrong placemen