IFC 'Save As' times

[owen]

We are experiencing extremely long IFC save times on a large project. This is not the first time I have encountered this issue but it is the largest project which has exacerbated the problem to a point we really cannot live with.

The project is a 45 story tower which is hotlinked via a set of .MODs into a container file in which the project is located in real world coordinates. These hotlinks break the model into 9 vertical sections of between 2 and 10 floors each. The visibility of each of these MODs is controlled with layer combinations, so when exporting say Zone 3 all other Zones have their Hotlink Master Layer off.

From here each of these zones is exported in 2 formats:

1. NWC (we have to save a copy of the file back to AC13 to do this export due to lack of a 14 plugin)

2. IFC


Saving each of these NWC zones takes approx 1-3 minutes depending on the size of the chunk .. all up i can save the whole building in 9 Zones within 20-30 mins.

IFC however takes 10-15 minutes PER ZONE to save! 90% of this appears to be the initial process of generating the IFC tree which does not seem to take account of what elements are visible but rather calculates everything in the file, regardless of layer settings. So for each of the 9 zones it calculates the entire model. Adding to this is the fact this process uses only 1 processor thread (of my AND it seems to slow/stall generation if I do not keep that session of ArchiCAD in the foreground - i.e if i Alt-Tab off to work in something else it takes even longer than 10-15 mins.

All up saving out an IFC model of our building split into 9 Zones takes between 1.5-2 hours if done on a single machine. We could of course get this done in ~20 minutes if we saved a single IFC model, but the project requirements are the 9 Zones in order to break things down into manageable chunks in both the consolidated Navisworks model and for sharing with project partners.

This would be managable if you could at least Publish IFC files (hit Publish and go home, files good to go the next morning). But of course you cant Publish IFC (you should be able to Publish any format you can do a Save As of IMO)

so

can anyone share any experiences / tips with IFC workflow on large projects particularly in relation to the weekly grind of importing/exporting the files. We have to do this process on a weekly basis on this project and I do not believe that it is reasonable to expect 1.5-2 hours every 5 working days be spent exporting a file.

sorry if that was a bit ranty but if Graphisoft are relying on IFC as their primary solution for interoperability as opposed to the Autodesk proprietary system then they MUST make the process of Exporting and Importing this as quick and painless as possible. Right now it isn't - we will probably look at sticking with NWC for Navis and simply giving consultants / subcontractors a 3D DWG instead (which can be published)

cheers,

owen

[Anonymous]

Hi Owen,

This is a long standing issue. Save times are significantly better in A14 though so assume you are using latest version.

I dont know of any work around except saving only what is essential to export. It is definately something Graphisoft will need to address.

[owen]

Mark,

Yes we are on latest build of AC14. Saving only what is essential is what I thought controlling the 9 Zones via Hotlinks would achieve but it seems to calculate them all prior to saving the elements I actually want saved.

A workaround to this I have not yet tried would be to have 9 separate files for each zone - maybe this would reduce save times. I really don't want another 9 files to manage but I will give it a go and report back.

cheers,

owen

[Link]

I don't think that changing the settings to 'Visible elements (on all stories), et al makes any difference either. Have you tried minimizing/maximising ArchiCAD during the Save As IFC process?

I've noticed that all (master) layers will become momentarily visible, like revealing what ArchiCAD is doing behind the scenes.

Cheers,
Link.