2018.1 IFC/3DS Import - Data loss

[Anonymous]

Hi,

First problem :

When I import my IFCs 2x3 (composed of IfcSlab only), they are not georeferenced correctly. The system of coordinates is correct though.

The IFCs have been verified on a few viewers, and they only lose their data when importing in IW.

The IFCs are imported with close coordinates to avoid geometry problems.

So I converted them to .3DS using eveBIM, but then, second problem:

When I import my 3DS, I lose all the data in it and the 3DS is monobloc. All my road platforms are merged in one and only and it's a real problem for me! I lose the volums, the opportunity to put textures, etc

It's also a problem because I want to export my model to TwinMotion and if the project road is monobloc, i can't put textures on TwinMotion neither.

Thanks

[FrankHuang]

@Anonymous , could you please share your IFC file so that we can take a look? 

for the second issue you mentioned about road, are you modeling your road using Civil 3D?  

Have you tried component road feature in InfraWorks in TwinMotion? 

[Karsten.Saenger]

Hi @Anonymous ,

do you use a cloud based IFC import or the local Navisworks import option?

Regards,

Karsten.

[Anonymous]

Hi @Karsten.Saenger and @FrankHuang,

I tried both, when I use the local Navisworks the IFC comes in the right place. But I still lose all the data in it and there's some geometry/texturing problems.

My IFCs come from a french infrastructure software called Mensura (from GeoMensura). But as I said, the IFCs have been verified through different viewers and there was no problems in the structure.

Ive written documents about my tests, could share too, such as my IFCs. Can I have your mail address?

[Karsten.Saenger]

Hi @Anonymous ,

I will share a OneDrive folder with you to upload the files.
IFC import from cloud is different compared to IFC import with Navispworks.

There is an Option in Navisworks for IFC file import, could you please switch off "Revit IFC" and test again?

When you say you loose all the data in it, do you refer to any metadata or attributes?
Please take a look at the following site that shows what entities are supported with an IFC import:
InfraWorks Help: Supported File-Based Data Formats

Regards,

Karsten

[Anonymous]

The Screenshot above comes from the test with Navisworks local import switched off. If it is switched on, there's a problem of georeference.

But even when I import it successfully, there's geometry issues.
That's why I import .3DSs

I lose all the data (attributes) like volums, area, etc. and the biggest problem is that the model comes in kind of "monobloc" so it's impossible for me to separate the different road platforms and to affect textures to the different platforms.

The only way to make it work is to import directly my models in TwinMotion but I lose all the environment created with Infraworks and my datasources so it's not worth.

What I would love to get is my IFC with all his attributes, well-georeferenced, the platforms separated, and no geometry issues. I'm also in touch with Mensura developpers, they are working on their side but it seems like there's a real IFC import problem in Infraworks, in fact, there's no issues when importing to viewers.

Looking at what is supported in Infraworks (in the IFCs), everything I need should show up (my attributes and my volumic plateforms).

[Karsten.Saenger]

Hi @Anonymous ,

thank you for sharing the data.

The geometry corruption looks like to be caused by the use of large coordinates. This is explained in the following knowledge base article:
https://knowledge.autodesk.com/support/infraworks/troubleshooting/caas/sfdcarticles/sfdcarticles/Inf...

Basically, if your IFC file data is located close to X,Y = 0,0 then the geometry will appear just fine. It should be possible to move all data by a delta -X and -Y before you export. In InfraWorks, apply the same delta +X and +Y as shift in the data source configuration.

The explanation why you don't have "access" to all single elements in the IFC file is, because InfraWorks treats the IFC file as one 3D model file. It cannot extract and sub-divide all elements of the IFC file. The workaround is to create as many IFC files as you need to see as separate 3D models in InfraWorks.

How about importing the IFC into Civil 3D. There you could explode the model into single parts. You will get 3D faces and you could create Civil 3D surfaces from 3D faces. In InfraWorks, these surface could be loaded as real terrain that integrate into the model nicely. You could use the surface boundaries as coverages for the textures.

Only disadvantage is that you will loose the attributes again.

Maybe there is a workflow to export from "Mensura" directly into Civil 3D that preserves more attribute information?

What coordinate system does the data have?

Best Regards,

Karsten.

[Anonymous]

Hi,

The thing is that the IFCs are already exported from Mensura with relative coordinates (with a base point in the project). However, I will try to export from the base point but with a shift by adding a "-" to the X,Y and Z.

Losing the attributes by creating a link through C3D isn't so bad, because the most important thing is adding the textures. I will try to find how to do this. What's the export needed from C3D after that?

The coordinate system is RGF93.CC48.

Thanks

[Karsten.Saenger]

Hi @Anonymous ,

my initial theoretical concept was to create a Civil 3D surface of your IFC file:

• Load the IFC file into Civil 3D - it's placed at the correct location automatically
• Explode the AEC_SLAB objects to blocks - explode blocks to 3D faces
• Now it's possible to create empty surfaces in Civil 3D and add 3D Faces as objects. You can make selections of surfaces based on layers.
• The difficult works is to create boundaries for the surfaces. It would be great if you can get them from your 3rd party program. It should be able to create these from the corridors. Maybe you can even create LandXML surfaces there.
  If you only have the IFC file here is a possible workflow to create the boundaries:
  • MAPEXPORT the 3D Faces as Shape Polygons - best if you FLATTEN the triangles first
  • Load MAPWSPACE and add the shape file
  • You can merge the GIS objects as needed
  • Note: This process is very sensitive if you have many object. Best is if you select a maximum of 1000 objects at a time.
  • Once all GIS objects are merged, you could get the outer boundary and use it as Civil 3D surface boundary
• Load the Civil 3D DWG into InfraWorks and the road surface should merge nicely into the existing terrain
• Load the road coverages - derived from the surface boundaries - and assigned the textures as needed

After testing that workflow I realized that it's not really suited for the IFC data you have. If you explode the IFS you get 3 different road layers with a top and bottom surface. It's a lot of work to clean that data to only have the very top 3D faces.

I checked the Import/Export possibilities of the "Mensura" Software and you should be able to directly export to DWG or use the LandXML exchange format. I believe if you use these options it will be much easier and you will be much quicker in Civil 3D to create a surface that can be used in InfraWorks. Maybe, you could even load the surface into InfraWorks directly (via LandXML).

Regards,

Karsten.

[andrewofabley]

@Anonymous 

I have experience moving IFC's with full attribution from external products into Infraworks and onwards to Twinmotion.

Happy to take a look also, if you can provide me with a link to the data.

[Anonymous]

Hi @Karsten.Saenger,

I've uploaded a DWG with only top and bottom 3D faces. I wanted to try the process from your last message, but an error appears "command in progress"... I've tried some solutions from the Autodesk Knowledge Network, unsuccessfully.

The DWG export from Mensura exports the terrain with it so it's not feasible for me.

The LandXML export from Mensura can export the platforms but it's recognized as a Terrain by Infraworks (can't change the category).

The C3D workaround seems to be the only viable solution.

Thanks

[Karsten.Saenger]

Hi @Anonymous ,

the LandXML export from Mensura sounds like it is what you need.

My suggestion for a workflow is:

Load it in Civil 3D as surface. Then extract the surface boundary. MAPEXPORT the boundary and load it as coverage into InfraWorks. These coverages can be textured. Load the LandXML in InfraWorks as terrain.
In newer versions of InfraWorks you can handle terrain data sources on different layers. This way you can control if the data sources are merged with existing terrain of not.

Regards,

Karsten.

[andrewofabley]

I've looked at a few ways of exporting this data, and I agree with @Karsten.Saenger  that having a multi-layered IFC is not ideal.

I can certainly deaggregate this data from IFCslabs, and reaggregate it by an IFC attribute before pushing it out to twinmotion via FBX.

Clearly, once exported to standard 3D formats, the spatial positioning of data and its attributes are not easily retained - but typically less relevant.

I quite like @Karsten.Saenger's idea to bring it back in as surfaces, perhaps as a method of rebuilding a hierarchy in Twinmotion based on texture.

[Anonymous]

Hi,

I found a way similar to the one you've given to me the past week.

I imported an IFC in Civil3D with no structures in it (only 1 block per platform).

I just had to isolate each type of platforms and make exports for each type of platform in DWG (3D Objects in Infraworks). But I had to set an offset to avoid the far coordinates issue.

The import in Infraworks is OK, but not 100% perfect (some files have a small Z offset of a few centimeters).

Secondly, there's a kind of void between some platforms/DWG files that doesn't exist with the 3DS process I've explained earlier on.

Thanks for your feedbacks again!

[Karsten.Saenger]

Hi @Anonymous ,

I did not think of separating the platform blocks into different DWG's and loading them in InfraWorks as separate files.

The difference to my workflow is that you have a 3D model and not a terrain surface. A terrain surface in InfraWorks can be used and it's possible to drape objects on and to change it. A 3D model is geometry only, that cannot be edited.
The gaps you see could be caused by rounding issues - or coordinates system related. Please be aware that a 3D model in InfraWorks only has one insertion point. The model is placed correctly with and at this point. But the larger the extent is and the further you are away from the base point, the geometry deviates, due to earth curvature.

Regards,

Karsten.