@Christie.G
I've experienced this personally and empathize with your frustration. Would you please let me know what version of Civil 3D you are using when experiencing this issue? Here's a screencast from @Matt__W posted a screencast that shows where to find the version information including what updates are installed.
Here's a screen capture of the information I'm requesting.
Civil 3D About
The majority of times that I've seen this happen is in a template that was created from acad.dwt. This is what was causing issues in our drawings and we resolved it in future drawings by creating new templates from the NCS "out of the box" standard template provided by Autodesk.
The majority of times that I've seen this happen is in a template that was created from acad.dwt. This is what was causing issues in our drawings and we resolved it in future drawings by creating new templates from the NCS "out of the box" standard template provided by Autodesk.
I suggest you try @jporter's simple workflow to test this theory.
- Create one site
- Draw two feature lines on that site
- Create a new site
- Move one of the feature lines to the new site
- Your first site disappears
- Save and close the drawing
- Reopen the drawing
- The feature lines may/may not be there
- A PURGE definitely deletes them
@jporter also has some good troubleshooting steps described here: Re: feature lines disappearing I've slightly modified his list and added a few more from other forum posts and troubleshooting discussions with Autodesk.
- Was the template or drawing you're using created from acad.dwt or the standard NCS template?
- Do you use a DNS replicating device?
- If it's only happening in specific drawings, what is common between those drawings (many feature lines? many surfaces from feature lines? many sites? feature line styles being used? crossing feature lines, etc., etc.)
- Have your run a RECOVER on the drawings (if your drawing has xrefs use RECOVERALL) to see if there are any errors it finds?
- Use the -PU command and purge all Regapps in the drawing.
- Do the feature lines disappear after a specific command or sequence of commands? If so, you may want to post the drawing here so we can test as well.
- Do the feature lines appear fine and then only when you come back the next day they are gone? If so, that could very possibly be a network or system issue.
- Do you reboot your system regularly?
- Was any anti-virus software running during install of the software or updates?
- If you have anti-virus software running now, do you have exclusions setup for Autodesk software?
Please let me know if the issue is acad.dwt related. If not, we can work through the other items listed and see if there's another cause for your specific drawings. Also the version of Civil 3D you are using will be useful in the troubleshooting process.