IFC & Custom Properties - Will Revit Accept & Display Them?

[jason.teagle]

If I define custom properties and property sets in an IFC file for an instance of a built-in family / type, will Revit honour them? Will it display them in the Properties palette when you select the object? 

My reason for asking is that I've done just that, but it won't show in Revit when I select the 'timber'. Since it's only a few lines here is how I defined the property / set / association: 

#1294= IFCBEAM('7TU2IR1$kKkneop_WXVGoX',#25,'Timber:114x114:114x114:213585',

'Noggin [ILB]','Timber:114x114:213547',#1293,#1288,'213585');
#1296= IFCPROPERTYSINGLEVALUE('Role',$,IFCLABEL('Noggin [ILB]'),$);
#1297= IFCPROPERTYSET('gLIEiEe8BEIDuGm77fIVHW',#25,'My Properties',$,(#1296));
#1310= IFCRELDEFINESBYPROPERTIES('fjhzLMbukndrcmkIxltcqe',#25,$,$,(#1294),#1297);

(The line break in #1294 is only for formatting, it's a single physical line in the IFC file.) 

As far as I can tell this is correct as that appears to be all that an export of a single timber from Revit does per property set. Note that I have not included any of the other properties that Revit automatically assigns and exports - but I can't imagine it requires these to add custom ones. 

I notice that an extra set called IFC Properties containing the object's GUID is included. I also notice that even when I exported no properties whatsoever, Revit automatically listed a bunch of its own in various sets - I'm guessing these are default beam ones? 

I know you can define custom properties for a built-in family through an add-in, so I feel sure it should be possible through IFC. If it simply isn't, if I create a custom family and type and used that, would that then make it possible to add custom parameters? 

[gopinath.taget]

Hello,

I just responded to the case you logged with ADN separately but I would like to repeat what I mentioned in the case:

*-------------

I did a little bit of research and could not find a lot of information on custom IFC properties and type parameter issues on export.

Before I pass on the question to the engineering teams, just wanted to know if you are doing any of this using the API or are you only using the UI for this? If you are using the API, can you please provide us with a sample to demonstrate the problem with custom properties and IFC export? Please do make sure that the sample does not contain any confidential or proprietary information.

*-------------

Let us continue the discussion in this forum case so we can include a larger audience.

Best Regards,

Gopinath

[jason.teagle]

I would just like to clarify that my problem is with *importing* IFC files into Revit - and the fact that they don't appear to use the properties set out in the file. I can confirm that both Revit Architecture 2013 and 2014 exhibit the same problem. 

Attached is a fully working sample IFC file that demonstrates the problem. It creates an IFCBEAM, and attempts to attach a property set called 'My Properties' containing one property, named 'Role' that should have a value of 'Top Rail': 

#85= IFCBEAM('AagB$G9y$QF4TO3NFybCXp',#25,'Timber: Top Rail','TIMBER - 140 X 38 C16','Top Rail',#84,#79,'TopRail');
#87= IFCPROPERTYSINGLEVALUE('Role',$,IFCLABEL('Top Rail'),$);
#88= IFCPROPERTYSET('wvoRPXl5p9Oc_R0GJbDdN0',#25,'My Properties',$,(#87));
#124= IFCRELDEFINESBYPROPERTIES('4e38jOuZp0EnJxCoXT_CxU',#25,$,$,(#85),#88);

If you import the attached IFC file, that property set / property value never appears anywhere. 

I did another test, and it is not just for custom imported IFC files; Revit's built-in objects have the same problem. I started a new project, and drew a single Universal Beam. I changed the 'Mark' property under 'Identity Data' to say 'Hello'. I saved the project as a Revit project, loaded it back, and it correctly showed 'Hello' for that property. I then exported to IFC, and the exported IFC does indeed say 'Hello' - but if I then import that IFC file back in without modifications, the 'Mark' property is blank - it has not used what is in the file. 

It is my understanding that if the same propery set name and property name are used as one supported natively by Revit, then any value in the IFC file for that property should overwrite what is in Revit. Any that have different property / property set names would then be added as extra properties. 

So it seems to be an IFC import problem across the board - hence why I submitted it to AutoDesk as a support case, as it appeared to no longer be something I was doing wrong. 

 (BTW, the forum doesn't like attaching IFC files - that seems to be an extension it has missed from its list.)

[jason.teagle]

I am able to confirm that Navisworks *will* show the custom properties. It will only show the property values as long as they aren't empty strings, but it will always show the custom categories. This implies that the IFC portion is correct (ish).

[gopinath.taget]

Hello,

I am currently working on the issue.  I will get back to you as soon as I have some information. Thanks for your patience.

Best Regards

Gopinath

[gopinath.taget]

Hello,

Sincere apologies about the delay in getting back to you. I am consulting with the engineering team about this issue and they are looking at it. Here is a partial response I got from them:

*------------------

there are a couple of issues here:

1. Revit does not roundtrip its own parameters via Open IFC.  There was an initial reason for this that seemed reasonable at the time, but over time, it has become clear that the opposite would be better.  For Link IFC (available probably in the near future), these parameters will probably be round-tripped.  For Open IFC, they will eventually also be round-tripped, but that hasn’t been done yet, and no ETA for it.
2. Revit does not have the ability to create custom parameter groups.  So for custom parameter groups, the parameter won’t show up.  The parameter itself should generally show up under the “IFC Parameters” built-in parameter group.
3. It is surprising that “Role” wouldn’t show up at all, so if we can get that IFC file, we could investigate why it doesn’t.

*------------------

I passed on your IFC to them and it is being investigated. Unfortunately I do not have an estimate on when I would get a useful response from the engineering team. But I am continuing to follow up. I will update this forum topic as soon as I learn something.

Apologies again for the delay and many thanks for your patience.

Thanks

Gopinath

[gopinath.taget]

Hello,

Many thanks for your patience. However, I do not have very useful information. The engineering team has noted that "The short answer is that it is on our list, and that the developer is likely not doing anything wrong". 

You could check back to us from time to time about the status of the issues but it is safe to say that there are no problems with your IFC file.

Sorry for not being more helpful.

Thanks

Gopinath

[npackham]

Any update on this? I'd like to supply Revit with a 'mark' and 'type mark' via an IFC file. As with the original poster, I'm referring to IFC being imported into Revit, not exported from Revit.  I can see in the export dialog there are options for exporting Revit properties like 'mark' and 'type mark', and I see them in the IFC content, but when I import (open) that same IFC file into Revit, those properties are blank. So it does not seem that even those standard Revit fields are being 'round-tripped'.