Delete a Breakline from a Terrain Model Imported from Inroads

While I doubt that this is the issue, you can check that your Graphic Group lock is turned off.

Which version of OpenRoads are you using? Or are you using the OpenRoads tools in InRoads (which version)?

I'm going to assume that you imported the DTM using the "Import From File" command. With that being said, I also am going to assume you had the setting for the Import Options set to "Import Terrain Only", which may be the reason for what you are experiencing. That setting imports the features into the Terrain (used for triangulation), but it creates a "static" terrain and the features are not editable.

You have 2 options if my above assumptions are correct. Open the DTM in InRoads and delete out the features and then reimport that DTM again.  Or you can use the same "Import From File" command and set the Import Options to "Import Features Only" (No Terrain is created during this process). This will bring in the Features as graphics (without styles/ FD's) and then you can delete the features you don't want and then create a Terrain Model using the "From Elements" or "From Graphical Filter" from the remaining features in the CAD file.  This creates a Terrain Model that is linked to the original feature data and those features are editable and the Terrain Model can be easily updated to match.

Hope this helps. There is much to learn about these new OpenRoads Terrain Models.

-Joe

Thanks for the reply Joe. I may very well have had import terrain only checked. Honestly I made this terrain almost a year ago and it's worked fine but this is a huge job and recently one of my collogues notices an area that needed editing. I started with the original .DTM and fixed the surface in Inroads. It worked just fine. I named it the same thing and imported it into the terrain file as the same name as original. Somehow our corridor files knew it was different and all of a sudden none of our template drops worked. We contacted Bentley and their answer was to rebuild our corridor, which would take a month or more as this is a 5 mile long job. So now I'm stuck with trying to edit a terrain which may not even be editable. I may try and do as you suggested and reimport from file and recreate the terrain after I delete the breaklines. I'll report back Monday. 

My guess is you received a dialog upon importing the dtm that said to many elements to link to the terrain. I believe the cap is around 10,000. The rest are unlinked, which makes they uneditable in ORD. I ran into this a couple years ago on a very large terrain for a current project. We questioned Bentley about changing the cap and they said there are no situations where anyone would need that many linked features. ?????? So we need to empty the terrain and reimport the drum whenever we get survey updates.

FYI: I had occasion to use 3D graphics linked to a terrain model in Civil 3D. In order to get certain triangles to look correct, I had to manually add some 3D breaklines. Some time later, another user with edit rights, decided that those lines were unnecessary and screwed up my DTM. After that, we adopted a policy  of publishing the terrain to its own file with no linked graphics. If updates were required, the source files were used and the terrain republished. I'd be reluctant to adopt a different policy for ORD.