Friday, 30 September 2016

Revit and tin surfaces from Civil 3D

For many years I have been trying to get information from Civil 3D to Revit or the other way around. Things have improved over the years quite a bit but trying to turn TIN surfaces into topo was always a bit of a challenge. (to put it mildly)

But Civil 3D now has the ability to export to IFC. IFC and Revit are of course big friends... But to my surprise the IFC out of Civil 3D to Revit is rather usable. There is of course still the issue with IFC files and coordinates.

To get the coordinates right

The first thing I did is check the ifc file I created from Civil 3D in Navisworks with the same dwg. On first glance it looks fine!
Next I linked the IFC file into Revit. That imported the file to far from the Revit origin. (on a side note, I am trying to get the factory to provide us with the ability to be able to place a linked file with it's origin on top of the survey point.)
I went back to Civil 3D and I copy pasted the surface into a new file. In that file I moved a know point to the 0.0 (see image)
This known point I converted to millimeters.
X = 353265.125     Y = 402261.875     Z = 111.334 (meters)
X = 353265125     Y = 402261875     Z = 111334 (millimeters)

  1. Insert the millimeters values in a new revit file into the project base point . Link the IFC file into Revit.
  2. Export the moved surface to IFC
  3. Link the IFC file in Revit 
  4. To check the coordinates I drew a big floor over the edges of the surface.
  5. Open a 3D view
  6. export that floor to a nwc file. 
  7. Apend it in Navisworks.
The nwc from Revit is right on top of the original dwg file from civil 3D (the one that was not moved!!!) That happens because of the numbers I filled into the project base point and when I export the the nwc file I had set the nwc settings set to: Shared (do not use project internal)

The big advantage of IFC files over other linked CAD files is that IFC files are properly cut by a section view!
(in this section view I have set the the far clip offset to 1 mm)
If you have trouble seeing you IFC file check the phase of the view

There are some things left: 
  1. I have to test the materials. When I set the view to shaded it's completely black.
  2. The IFC file is a Generic Model and not a Topo surface. (personally I don't care)

But image what you could do now if you take the different surfaces from Civil 3D to Revit!

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