Civil 3D DEM import issue

I successfully imported the Clairmont Canyon Demo Project DEM into C3D but the one Rock surveyor created for my project says its an invalid DEM file. Only difference in the two is the the Clairmont project does not have a vertical datum. UTM 11N. Mine is also UTM 11N but has NAVDD 88 Geoid 12b. Anyone have these issues?

Still have not figured out the DEM issue, working with Rock on it. I did come up with a work around for what I was trying to do. I wanted the TIN that DEM was created with. Under “EXPORT” after you completes Rock Surveyor processing you will have the option to export the vector data for the DEM which is simple CAD points with enough density to create a great surface. You only need to use the GROUND ONLY in Rock Surveyor.

I recommend checking out virtual surveyor. It’s really handy for getting a lidar dtm to a manageable size for CAD, and has some specialized algorithms for selecting points (q-points) and defining breaklines. Plus its also just great for QAQCing your surface


I am having the same issue. C3D just says “unable to read file” when I try to create a surface from the downloaded DEM .tif from Rock. I also dont see where to export ground surface vector data like you are describing. Is there some way I can get more info on this?

This was a bug that has since been fixed in the Rock Cloud. All that you need to do to get the updated file is to re-trigger processing. That can be done by simply:

Move the point cloud 1 cm and click reprocess
Then move it back and click reprocess once more.

You’ll now the updated .tif files that should work in C3D.

Refer to this article for more information.

Update: the new useable dem .tif files are working great. They are extremely dense for civil 3d, but they provide mush more accurate surfaces to work with. I have been using it to create point grids and breaklines within Civil 3d, and then rebuilding a “lite” version of the surface that I can send to my engineer clients.