Set Origin E/N when exporting IFC from ggRhinoIFCLayers

Hi All and Jon,

Is there a way to set the Eastings and Northings coordinates at the (local) Origin when exporting from ggRhinoIFCLayers?

I find this way much faster and more flexible than using the Grasshopper components (I am manually creating the geometry as breps).

I used to move the model to the World Coordinates before exporting but this does not work when the model is imported in Revit (Revit internal origin should match the Rhino local origin).

Thank you
Giovanni

Hi Giovanni,

I still personally advise to export from Grasshopper even if all the modelling is done in Rhino, but direct export is something we support (and want to improve).

It’s possible to nominate a project base point using named cplane in rhino. There is a command ggIFCNamedCPlane where you can nominate the eastings, northings and rotation (I’ve used the term True North to be consistent with Revit but really it should be Grid North as I understand it). Note the units need to be in Rhino.

As an example, if I check in Civil3d I get coordinates of E 334888.932 N 6252291.651 (in metres) for the Sydney Opera House in MGA/20CD-56.

If this is the project base point, I can set a named cplane using the command above, and then export nominating the cplane, configuring that model is in local coordinates.

Here is an example 3dm.
230425 mga20CD-56.3dm (88.7 KB)

The resultant IFC then sets the transform on the Site, which is where revit/navisworks expects it.

IFC4 has improved attributes and relationships for georeferencing a model, but as you’re using IFC2x3 Coordination View, placing the coordinates on the site is common practice (even 2x3 has a better way of supporting this but it’s not typically used).

Let me know if this example helps or not, or if you don’t get the output you require.

It would be nice if Rhino natively better supported georeferencing models, particular when importing or linking other cad files. If you have preferences other than named cplane to mange this, let me know.

Cheers,

Jon

Thank you very much Jon.

Using the ggIFCNamedCPlane command has fixed all the issues with the exporting.

Giovanni