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Using IFC files with Solid Edge ST8

Francis Robert - Tuesday, February 02, 2016

Solid Edge ST8 can now import and export « IFC » files. This “Industry Foundation Classes” format is actually a neutral 3D file which allows sharing geometry and properties between a CAD tool and “BIM” applications (Building Information Modeling).We could compare an IFC file with a STEP file for example; difference is that the IFC format also contains a suite of properties used in the Construction and Architecture industries.The IFC format is developed by an international committee and is not owned by any CAD vendor in particular, therefore the “neutral” file nickname.

 

Solid Edge ST8 supports two types of IFC files, IFC2X3 and IFC4. The IFC2X3 type doesn’t contain precise geometry (Brep is NOT supported) and less properties.This type is closer to a STL or JT (without precise geometry) file.Whenever it’s possible, it’s better to use the later IFC4 type.It’s more recent, does support precise geometry (Brep) and can carry more properties.These properties are closely tied to the Construction industry, like electrical consumption for example.The application that reads the IFC4 type will be able to add the geometry to its general layout, automatically going on the correct Field / Building / Story, adding the electrical consumption to the overall building consumption, for example.Please note that you need to install Solid Edge ST8 Maintenance Pack 3 in order to manage these additional properties.


1. Simplification

 

We strongly suggest simplifying the geometry before exporting the model to the IFC format.While you can always export the model as is, your partners and customers will appreciate the fact you took some time to remove unnecessary details (hardware, internal components, etc.). When your product is positioned into a building, you can remove details without impact.By simplifying geometry, the global performance will be much better and you won’t share all the fabrication details (and intellectual properties) with your customers.

 

Solid Edge offers efficient simplification tools at the part level as well as at the assembly level. This allows you to remove faces not required in the final model (chamfers, fillets, internal details, etc.) while keeping a single file per part to maintain.

 

Solid Edge will export the IFC model in its « as displayed » state. So if non-required parts are displayed, you should hide them before exporting, check the correct option, and the IFC model will look exactly as you want to.Same thing applies to the “Design” or “Simplified” display state of parts.


2. Properties management

 

Before exporting to IFC format, you need to make sure the properties are defined correctly.This is the primary purpose of this format.If there were no benefit in sharing properties, you could simply use existing neutral 3D formats like STEP and Parasolid.

 

For type IFC2X3, the list of properties is limited to Author, Organization, Program and Description). We access these properties via the IFC export options.In Solid Edge, select Save As, then the IFC format and the Options button will become available.

 


 

Type IFC4 is more recent and can carry as many properties as desired.Again, in the IFC export options, you can select « Include IFC properties ».This enables the link to an Excel spreadsheet used to define properties groups, names, types and values.We can have as many spreadsheets as required.

 


 

The default XLSX file supplied with Solid Edge is located in the Program sub-folder of the ST8 installation folder. There are instructions in the first tab and a suite of properties given as an example.We suggest backing up this file and using it as your foundation to define your own list of properties.

 

Each of the following tabs is used as a property group. Each group contains a list of properties, each with their name, value and type.You can create and remove groups and properties to make sure to cover the needs of each of your projects.For multiple customers with different needs, we suggest to create a spreadsheet for each one of them.You’ll only need to select the appropriate spreadsheet when exporting your model.


  • Portions of the default XLSX file supplied with ST8 MP3:



  • For example, group « Pset(Common) » contains general properties for every basic IFC file. Another groupe like “COBie” (Construction Operations Information Exchange) corresponds to generic properties used in the Construction industry without regards to actual geometry.


3. Export

 

Once the model is simplified and the properties correctly defined, you just need to hit « Save ».You’ll see file size compression in the process, especially with the older IFC2X3 format.


4.Import

 

Solid Edge ST8 can also import IFC files.You will probably see additional assembly levels than the model you exported. Since IFC format is aimed at Construction projects, it will add a couple of levels of sub-assemblies above the actual model.They correspond to Construction Site / Building / Story.This allows architects easier management of building components.

 

If you import an IFC2X3 type, you won’t be able to select the geometry in Solid Edge.This is because the geometry is faceted data, not precise geometry.You only have the « visual » portion; there is no « mathematical » portion (Brep).Therefore, the IFC2X3 usage is very limited when opened in a CAD tool but you can still use it as a reference. You will not be able to select a keypoint, create a draft, display visible edges or even do a boolean operation.This is similar to the usage of a STL or JT (without precise geometry) in Solid Edge.

 

If you import an IFC4 type, you will remove the limitations mentioned above. IFC4 contains the “Brep”, so there is precise geometry in the file.You’ll be able to use it as with any other imported CAD format, similar to a STEP or Parasolid.Even the parts’ colors will be imported.

 

As you see, we strongly suggest using the IFC4 type whenever you can.


5. Conclusion

 

With a couple of tries, you’ll be able to find the right balance in the level of details (what do you simplify?) and the list of properties to share with your customers and partners. You’ll be able to share your products intelligently with all architects on the planet in a complete and precise fashion.


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