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Stéphane

Trouble exporting in IFC

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Hello, 

 

I have troubles exporting my VW file in IFC for my engineer working on Revit. 

 

History of the events 

1- I exported once an IFC file and re-imported it in VW to check if it worked. It worked. 

2- I exported my drawing in IFC2X2, IFC2X3 and IFC4 to be sure my engineer could read it. Tried to import them back in VW : didn't work. Error or no visible geometry in the file, even if the files were heavy, respectively 595 Mo, 1 Go, 7.7 Mo.  

3- Send them anyway to the engineer, hoping it was a VW import issue. 

4- Engineer couldn't read any of my files and sent to me the screenshot below. 

5- Sent to engineer an additional SAT and RVT export. Error while opening the SAT file. Missing stories and walls in the RVT file. 

 

My hypothesis is that the issue comes most likely from my VW file. I'm not sure if this could be a hint but the first time I exported it, it asks me to assign layers to stories. Since my file was not organized by stories, I quickly created one and randomly picked one layer and assigned it. Surprisingly, it worked (see point 1). But then I wanted my file to be clean, so I reorganized the layers in question by stories and re-assigned them properly (?). From there, I couldn't import the exported IFC anymore (see point 2). 

 

 

 

image001.thumb.png.ff1cd14a4a176cb4c15a3426e21ca96c.png 

 

 

PS : 17'727'024 errors... 

Edited by Stéphane

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Hello again, 

 

After further tests, I discovered that my issue might be related to Design Layer Viewport. I could imagine that IFC files hate DLVP

 

I have 12 buildings. I need 3 buildings to be exported. The 9 other buildings were erased for the test. Building n°1 is a regular drawing. Building n°2 is a DLVP of another building (erased in my new test, so the DLVP is empty which means we actually don't see the building n°2). Building n°3 is a DLVP of Building n°1. 

 

I exported the test file in IFC4, with the "only export visible objects" option. Interestingly enough, I can now import the IFC file again and it works. BUT : None of the DLVP are visible, neither the Building n°2 (as expected) nor the building n°3. 

 

Does my first issue (see first post) occurs when "only export visible objects" is ticked and the source of a visible DLVP is not visible ? 

 

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No, IFC loves DLVPs. I have been exporting loads of stuff organized across files using DLVPs for a large project.

Visibilty: meant is the visibility in the class and layer list.

A design layer that you see because it is the active layer (you are IN it), but is invisible in the layer list, won't export. Does this resolve your issue?

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8 minutes ago, _c_ said:

Visibilty: meant is the visibility in the class and layer list.

A design layer that you see because it is the active layer (you are IN it), but is invisible in the layer list, won't export. Does this resolve your issue?


Thank you for this input. I'll check this (I'm away from my computer). 
 

Since we need to assign layers to stories in order to export to IFC, how do you assign DLVPs to stories ? 

my file is organised like that : 

- For my whole drawing, 1 layer = 1 story
- Building n°3 is a DLVP of building n°1 which has several layers. This DLVP is on its own layer "Building n°1 DLVP


How to assign this DLVP which has several layers "Building n°1 Floor1"; "Building n°1 Floor2"; etc... to stories ? 
 

Looking forward to read you. 

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You should also only be exporting one building at a time...

Edited by shorter

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22 minutes ago, Stéphane said:


Thank you for this input. I'll check this (I'm away from my computer). 
 

Since we need to assign layers to stories in order to export to IFC, how do you assign DLVPs to stories ? 

my file is organised like that : 

- For my whole drawing, 1 layer = 1 story
- Building n°3 is a DLVP of building n°1 which has several layers. This DLVP is on its own layer "Building n°1 DLVP


How to assign this DLVP which has several layers "Building n°1 Floor1"; "Building n°1 Floor2"; etc... to stories ? 
 

Looking forward to read you. 

 

Stephane, I can answer better tomorrow morning early, but first off:

  • you can only map design layers to stories
  • you can have as many DLVPs as you need in the design layers that you need to map
  • BUT: 1 DLVP for each referenced floor, placed into it's own Design Layer (that's where I usually think I want to change application). As you see, you are compelled to reconstruct quite a lot using DLVPs and layers.
  • be very careful with the elevations of both DLVPs and design layers (do make some tests)
  • you cannot have different buildings in the same file IF they don't have exactly the same story structure Edit: elevations.

 

 

Edited by _c_

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Thank you very much, @_c_ and @shorter, for your answers. 

 

Breaking news

After analyzing my IFC file, I discovered that some layers were duplicated 2 or 3 times on my Building n°1. The amount of duplicated layers equates the amount of missing stories that come from DLVPs. In other words : my DLVPs stack on its sources (Building n°1) instead of position themselves correctly to form my Building n°3. Why ? 

 

I still have the feeling that IFC is not DLVPs friendly. Still curious how you managed, @_c_, to make it works. 

 

Our discussion is now focused on DLVPs but we still don't know why my test file can export an IFC (still with some issues but at least readable) and not my original one. 

 

Edited by Stéphane

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I believe I owe you at least some screenshots to help you understand my issue... 

 

1. VWX file

 2027822554_Capturedcran2020-10-1916_51_28.thumb.png.24cc03acb67b09a278fbaf6d81cc69ec.png

 

 

2. IFC file

 1084325996_Capturedcran2020-10-1916_51_52.thumb.png.ac9238e6dc6bddb6df69b9cc5f3136f2.png

 

 

By the way, why is my ramp (dark blue object) rotated on the Y axis in my IFC file ? (The civil engineer will kill me)

 

 

Edited by Stéphane

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Model at 0m.

 

Use DLVP to locate Model in true space.

 

Place DLVP on it's own layer with correct Z value, either using Stories or Layer Elevation.

 

Although very quick, can result in IFC storeys at the wrong level.

 

Happy to discuss offlist.

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@shorter, I'm sorry but I'm not sure to fully understand. I gladly admit that I am still a bit new to VW. 

 

What is true space ? 

 

I can say that the Z lvl setting of DLVPs is not very intuitive. If I set it to 0 or to its absolute correct Z coordinate (Z value in the IOP), then it moves completely off. I have to graphically set it back in place, but then the Z coordinate has a strange value (or negative either very high).

 

Layer 4: altitude 59680 cm (above sea) (this value is set in my layer organisation window)

Layer 1: altitude 58810 cm (above sea) (this value is set in my layer organisation window)

my DLVP comes from Layer 1 but need to go above layer 4. What should be its Z value (in layer organisation window and in IOP) ?  0, 58810 + 1160 (equivalent to 4 stories times 4), 1160, or something else ? 

 

Anyway, this is for the Z issue. How to explain the X and Y offset ? Why in my IFC file, the VLPDs stay at its orignal position ? 

 

 

Edited by Stéphane

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1 hour ago, Stéphane said:

By the way, why is my ramp (dark blue object) rotated on the Y axis in my IFC file ? (The civil engineer will kill me)

 

🙂

 

I would think this is a bug.

 

I often see objects losing their position and collected at File Origin,

at least for Doors which aren't inserted in Walls,

or Stairs missing completely,

by IFC4.

 

(I was told here, that IFC4 is not yet ready for production.

Although I find the exported geometry quite better than with IFC 2x3.

at least for what will be exported 🙂 )

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Progress has been made, thank to your dedication, thank you. 

 

So, DLVPs from Building n°3 have been erased and replaced by regular copie/paste in place. Now it works. Conclusion : Issue comes from DLVPs. 

 

825550489_Capturedcran2020-10-1919_26_40.thumb.png.f2292144b225cc66cdd8164903f15481.png

 

 

I recap here my questions : 

 

- How to properly set the DLVPs in order to be exported in IFC ? For some reasons, my DLVPs stay at their source position (Building n°1) in my IFC file instead of forming my Building n°3 (like in my VW file). See my posts above. @shorter @_c_

 

- My test file (which consist of erasing most of my drawing) can export an IFC file and read it back, but my original cannot. Why ? Is it linked to this DLVP issue ? Is it simply because the file was too heavy (is it why @shorter you suggested to export the buildings one by one) ? Could it be that some objects are too complex (likes 3d trees) ? 

 

- About the weird ramp issue, your intuition, @zoomer was correct. Well done. It is an IFC4 issue. If exported in IFC2X3 this problem doesn't occur anymore. 

 

Little by little, with all of you, I start to see the light at the end of tunnel. Thank you. 

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I think it is best to check the IFC files in Solibri or similar,

to exclude what is an VW IFC export error from VW or Revit

import issues.

 

For me IFC 2x3 from VW seems much more reliable, with the

tradeoff of worse geometry or less true Solids than IFC4.

But I also had missing objects like parts of Stairs in IFC 2x3.

 

I think VW doesn't really support IFC Buildings or it doesn't make

sense when you need (different) Story Level Settings for each in VW.

So in VW I would also put each building in its own file.

 

 

And I don't really get why Revit or IFC imports in VW, VW will

lock the imported Objects behind Revit or IFC Containers,

where the IFC Tags are applied to the Containers and AFAIK

get lost when exploding/ungrouping these parts for access..

Edited by zoomer
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Hello Stéphane,

 

if I understand correctly what you did, you are exporting one building pro design layer. You assemble the buildings using one singular DLVP pro building, am I right?

Should that be true, please mind that while this might seem visually correct, the resulting IFC structure won't be. A multi-floor DLVP doesn't distribute automatically the layers into the proper storeys.

 

TBB_IFC_example.zip

I attach here an example of assembling stuff across various files. Please mind that this is a totally simple example, it won't be as easy in the reality. I used "old-style" referencing for clarity (and I prefer it for a number of reasons). There is:

  • a source file with some variants of floor plans (load repetitive content by reference into other files)
  • 1 file for building 1 (export from here building 1)
  • 1 file for building 2 (export from here building 2)
  • if there was a site plan, this would need to be exported as stand alone as well and the option "Export Site Model" to be enabled in the IFC Export settings.
  • everything is assembled in Solibri. Note: I just noticed that Solibri Anywhere 9.12 doesn't allow any longer to assemble files. Use 9.10!

I am for some reason kicked out of my Solibri licence and cannot check properly for collisions etc. Sorry if I let some ugly error around.

 

VW is not developed for multi-files projects and you'll soon reach its limits. It can be done, but it won't be fun.

 

About IFC 4: VW is certified for IFC 4 export, import isn't there yet. 

More here:

https://www.buildingsmart.org/compliance/software-certification/certified-software/

Depending on how strict your exchange requirements are, you might be better off with IFC 2x3 and since we cannot import properly what others send us, I definitely suggest you to agree upon IFC 2x3.

 

 

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I have done this morning additional tests, following your suggestions. 

For some reasons, I can now export to a readable IFC from my original file again, which includes DLVPs. The only thing I did in between was hiding more layers and class. I haven't even restarted my computer or VectorWorks. I guess that an objet in one of the hidden class is corrupted OR too many informations needed to be exported. I don't know for sure. 

 

 

2 hours ago, _c_ said:

if I understand correctly what you did, you are exporting one building pro design layer. You assemble the buildings using one singular DLVP pro building, am I right?

 

Yes, this is correct. To be slightly more accurate, the right side building is made out of 2 DLVPs : 1 DLVP for stories 1 to 4, another DLVP for story 5 (as shown in one of post above). As you can see on the pictures below, it works in IFC2X3. Surprisingly. 

 

 

2 hours ago, _c_ said:

About IFC 4: VW is certified for IFC 4 export, import isn't there yet. 

More here:

https://www.buildingsmart.org/compliance/software-certification/certified-software/

Depending on how strict your exchange requirements are, you might be better off with IFC 2x3 and since we cannot import properly what others send us, I definitely suggest you to agree upon IFC 2x3.

 

Very interesting informations. I will bookmark the link. Thank you very much. 

 

 

14 hours ago, zoomer said:

I think it is best to check the IFC files in Solibri or similar,

to exclude what is an VW IFC export error from VW or Revit

import issues.

 

Thank you for your suggestion, it helped me to understand the issue. I downloaded Solibri today (yes, I'm new to BIM). And here are the results :  

 

 

1. IFC2X3 

1825418884_Capturedcran2020-10-2010_58_57.thumb.png.a6080ca5c4dc1c931db02fbfc1002f23.png

 

2. IFC4

1621284177_Capturedcran2020-10-2011_06_50.thumb.png.7d2e3b9706fdb4683e53a5331e5b69cd.png

 

Important note : Last layer of Building n°1 (left), Building n°2 (mid) and Building n°3 (right) are made out of DLVPs. Several conclusions : 

 

- DLVPs are actually IFC friendly, but only in version 2X3. DLVPs won't work properly in IFC4. The building you see on the foreground, is actually my Building n°2 but positioned on its source (Building n°2 is a DLVP from this foreground building). This confirms my previous theory. 

 

- VW still has export issues in IFC4 (see ramp issue and DLVPs already mentioned) 

 

- It seems possible to use multistories DLVPs. There is at least no graphical bugs. I guess the issue will be that my Building n°3 will be considered of having only two stories (one made out of 4 stacked slabs). But since we are drawing in BIM level 1, it's not really an issue for us. Or I don't see it yet 🙂 I believe, as @_c_ suggested it, it would be more adequate to map only one story per DLVP to do things properly. 

 

 

Two good news : 

 

- I can now send an IFC file to my engineer 

- My engineer won't kill me 

 

 

Thank you very much for your precious help ! The BIM shower is a bit cold but it will be ok. 

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15 hours ago, Stéphane said:

Progress has been made, thank to your dedication, thank you. 

 

So, DLVPs from Building n°3 have been erased and replaced by regular copie/paste in place. Now it works. Conclusion : Issue comes from DLVPs. 

 

825550489_Capturedcran2020-10-1919_26_40.thumb.png.f2292144b225cc66cdd8164903f15481.png

 

 

I recap here my questions : 

 

- How to properly set the DLVPs in order to be exported in IFC ? For some reasons, my DLVPs stay at their source position (Building n°1) in my IFC file instead of forming my Building n°3 (like in my VW file). See my posts above. @shorter @_c_

 

- My test file (which consist of erasing most of my drawing) can export an IFC file and read it back, but my original cannot. Why ? Is it linked to this DLVP issue ? Is it simply because the file was too heavy (is it why @shorter you suggested to export the buildings one by one) ? Could it be that some objects are too complex (likes 3d trees) ? 

 

- About the weird ramp issue, your intuition, @zoomer was correct. Well done. It is an IFC4 issue. If exported in IFC2X3 this problem doesn't occur anymore. 

 

Little by little, with all of you, I start to see the light at the end of tunnel. Thank you. 

 

As @_c_ states, using DVLPs will not correctly assign levels to the DLVP in the IFC but it is an effective way to model quickly, and if the BEP is not too exacting, will export an IFC reliably otherwise.  WHen I say 'true space' I mean the DLVP is located at the correct level in the correct coordinate system, as opposed to flat packed where it is modelled at 0,0,0.

 

Every BEP I have ever seen will state that buildings must be issued separately. 

 

Do you have a company BEP?  Is there a BEP on the project?  We don't recommend issuing any IFC data without some sort of protocol agreeing to or defining what's going to be issued.  Others may take exception to the fact that you are bundling every building into one file.  The BEP gives them an opportunity to agree or not to that.

 

“Any additional information is considered waste” ISO19650.

 

Simplify trees to what others need to know, and do not ever use the VB Visual trees.  Only model what is useful for coordination and clash avoidance.  So size, quantity, and volume of tree pit, etc, is all that's needed.  COBie data may or may not be needed.  If you need to swap out 'fluffy' trees for 'LOD100' trees, there is a very effective method for this using symbols. 

 

Build it minimally.

 

You should prepare models for export and not just 'export' and expect it to work.  Models need to be cleaned up; sheets, views, extraneous data, resources, etc, and purged removed prior to export.  Do you have a model validation checklist?

 

Have you carried out any coordination tests prior to issuing the IFC?

 

IFC2x3 has always been more reliable in my experience.

 

Solibri Anywhere is great for reviewing multiple models.  I have also been referred to eveBIM.

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24 minutes ago, shorter said:

Solibri Anywhere is great for reviewing multiple models.  I have also been referred to eveBIM.

 

Steven, apparently with the latest version 9.12 you cannot load multiple files any longer. Don't override the old version, should you have one.

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