Civil 3D Earthworks surface from complex Revit model

[rjjohnstone]

I am creating a site earthworks surface and have been given a complex Revit structural design model. The model is comprised of ground slab with thickenings, troughs, service tunnels etc. Rather than having to go through the file to determine the 3D elements that sit on grade, is there a way to get an imprint of the solid model as if it was pushed vertically into a mould? I could obviously use this mould as the basis of my earthworks surface model.  

[Civil3DReminders_com]

It's been a while, but I think the Building Site Model should give you what you want. Revit has the option to export to an ADSK file and then you can then import it using the ImportBuildingSite command in Civil 3D.

[rjjohnstone]

Thanks very much, finally got around to looking at this. I have the model in Civ 3D as a building site as you described. It is really very complex. Can I extract a surface from this somehow as my earthworks imprint? or do I need to trace the very complicated footprint of the building and create a surface from these breaklines? 

[Civil3DReminders_com · Accepted solution]

I'm not sure at this point. If there isn't much variance I'd go into a 3D view and then snap to the appropriate locations to get the bottom. I'd also try exploding the Revit model to see if lines would be created by them selves and then you could delete the info you don't need.