IFC Export - Decompose composites to its skins

[Johan Stinckens]

When exporting an IFC to use for Information Takeoff (Solibri) I would like to have all composites decomposed to their skins, preserving their materials and the ID of the composite they belong to.

I have tried several combinations with either BREP or not, but can't seem to produce what is needed.

When selecting a wall I should not get the whole component, consisting of 3 decompose (forward) elements, but I should have three seperate objects.

I know I can select them seperately (Shift-click) in Solibri, but I need them to actually be seperated, retaining the name information from its "parent" and the material from itself.

IFC-Export_Decompose

[Erwin Edel]

There is a workaround to do this: you need to make separate IFC exports for each layer and one more for the rest of the model.

You can do this by turning 'participates in collission detection' on and off in the building material settings.

So let's say you have a bricks, air-space, insulation and concrete or bricks that make up the composite. You can leave out the air-space in collission detection all together and then make 3 exports showing only those walls for each material and one more export for the rest of your model. You then need to merge these 4 IFC files.

It is not ideal, but the other alternative currently is to model each layer seperately and that is even more work.

It is interesting to see that the need to have these be seperate is not exclusive to Dutch market, unless your project also takes place in NL.

[stefan]

Unfortunately there are some restrictions on what Archicad can deliver when dividing the element into its constituent parts.

Beware: the "name" you see is an auto-generated naming convention from Solibri (IFC Entity + Storey Number + Object Number) and is not controlled by Archicad at all! It is not even in the IFC file.

[Johan Stinckens]

Hi Erwin,

I would expect IFC exports to be able to decompose any composite or profile, regardless of local building practices.

Well, nearly in NL! Belgium. 🙂

[squall_tmo]

Hi Johan,

I don't know if it's exactly what you were looking for, but from AC25 update 2 you can export the Wall with all the components information called with the name of the Building Material:

so we don't need to explode skin components anymore to understand the name of the Material and all the rest of the related info!

I hope this may help!

[Johan Stinckens]

Hi @squall_tmo,

Sounds promising. Will have a look into it (currently stil operating AC24).

However, in your example I can't seem to find the length of each component!

They should relate to the length of the individual skins to be of any use.

Could you point me to where you set up the Archicad Properties to be included in the IFC. I seem to have "broken" one of the translators. 😞 

[squall_tmo]

I start from the question related to length:

I'm afraid but from what I know you can extract the height and the thickness of the component, but it's still not possible to extract its length (you cannot even in schedules).

In AC25 you can calculate the length "analytically" (out of Archicad obviously) because they added the "Gross Volume" and the "Gross Area" (obviously it's not exactly the same of a property printed out by AC...but it's better than nothing I suppose).

Talking about export settings I just set geometry conversion to never explode elements and in the Data Conversion I choose what I want to export, eg. Components Properties and Materials properties (I attached a couple of screenshot).

I hope this may be helpful!

[Steve Jepson]

  "I'm afraid but from what I know you can extract the height and the thickness of the component, but it's still not possible to extract its length (you cannot even in schedules)." 

But you can Schedule the Length of the Reverence lines and some other Wall Length fields - if that is any help.   I seem to remember using Length in 3D or something like that too.  ? 

[Johan Stinckens]

Indeed @Steve Jepson , you can schedule the length of the reference line.

But the given length is identical for each of the skins as there is only one reference line for anyone composite/complex profile, regardless of how many skins it has.

And for this to work we need the length of each of the skins, taking into account that wherever skins touch/intersect, the common area of these components are calculated only once.

I just can't seem to grasp why an export to IFC has no length attribute included?!

Is this an anonimity in the IFC standard?

[squall_tmo]

Thanks Steve for the suggestion!

I think that it probably depends on what they ask you in every different Nation/state.

They often ask you the dimensions of every skin, that are generally quite different from the length of the reference line, so this would be really useful in my opinion...

If the length of the wall is enough for the QTO it's possible to export it (and a lot of other info) by checking the "Element Properties" in the Data Conversion settings.