Exporting to IFC with local coordinate system with rotation

[MarkvyAB]

Is it just me or is this not a fully built in feature yet in Civil3D?! I mean, how hard could it be?

I have my 3D model that I want to export to IFC in the same local coodinatesystem that the architects etc uses.

This is my procedure:

1. First I export to 3d DWG

2. Change colors of all 3D faces (oh gosh...) so they look as I want them to look

3. Move and rotate to the same local coordinate system as the architects uses

3. Run the export command

By doing this I also get the triangles visible in the IFC which I sometimes don't like.

Please tell me I'm doin this wrong and there is a more correct way of doing this!

[SoaresASBCAD]

You're not doing it wrong—IFC export from Civil 3D still feels underdeveloped compared to what BIM workflows require. Many users end up using a similar workaround: exporting to 3D DWG, adjusting coordinates, and then exporting to IFC. The visible triangulation is a common complaint, especially when TIN surfaces are involved. Unfortunately, there isn't yet a seamless "export Civil 3D model to IFC in shared coordinates with clean geometry" workflow built into Civil 3D.

[navya_gelli]

Hello @MarkvyAB

Just checking in to see if you had a chance to review SoaresASBCAD response regarding the limitations of Civil 3D. Did it answer your question? If so, please consider marking it as the Accepted Solution. If you're still looking for more information, feel free to provide any additional details, and the community will be happy to assist further.

[MikeEvansUK]

You are going about / thinking about this the wrong way.

You are using the correct coordinate system (georeferenced), I assume the Architect is using Revit and in which case he has two coordinate systems.
Local Grid (0,0 close to the building) and TrueGrid (shared coordinates) which is the world coordinate system.
You export an IFC as True Grid then the Architect will align as Local via shared coordinate systems (assuming they understand how to correctly set this up).

On this, I would suggest inserting a Cube somewhere at a known and agreed coordinate location (building grid & FFL) in all transferable models. This cube can be used to confirm or align if any errors.
Drawings will not have the same coordinate system or that is Revit will not know they have so always aligns using Centre to centre.

On the Surface, if you have Revit 2026 + you can convert Faces to TopoSurfaces but the conversion is a little ropey and allows some selections but not all in one go (not sure why, to solve I coded a workaround that tests and removed faces from the model before adding to get around this).

Otherwise and frankly you're stuck with Faces for a surface but I would not use an IFC for a surface, for this I would export the faces and convert to regions.
Then import as a GenericMass as using this route, you can then annotate the levels or falls on the surface model.

The Architect should never use an old type Toposurface or new Toposolid from the points (from triangles) it will result in an incorrect surface model unless the surface is flat. 

Mike