Disappearing Feature Lines

[Christie.G]

I have read a number of forum post regarding disappearing feature lines, but have not had any luck finding a solution. Is there any progress on preventing this from happening as I have read on the posts that this has been a problem since 2007 and every version since.

This is a very costly problem due to time spent reconstructing the feature lines so if there is a fix or a way to prevent this happening could we please get an update.

[C3D_TomR]

@ODO18 

Does it make a difference if the feature lines are Siteless (Site set to <None>) or in a dedicated site?

[vaughan.giles7AGEV]

I have subsequently found out through a senior designer that it is related to a hard-wired error in Autodesks coding relating to the use of grading tools - lets just say if you have a gradings that have something crossing it (grading / feature) - you're about to have a very bad day.

The grading tools should ONLY EVER be used to initially create what you need and then you EXPLODE the grading and use the featurelines for your model to make sure this error never happens again.

In 20yrs time when Autodesk fix this error I may return to using the grading tools for an end product.

[Anonymous]

No, that does not seem to make a difference.

[Anonymous]

Grading Objects have gotten a little better.  I instruct all the designers to never let them touch another grading object.  I also never select the entire feature line.  I always only do it along a portion.  For example if I have a feature line that has parking islands, I would stop daylighting before it get to the island, then pick it up again on the other side.

Using these rules though I have found them to be much more stable.

[Anonymous]

I agree @vaughan.giles7AGEV . I too have noticed grading tools cause further errors and have adopted the "initial use, then explode" to avoid errors. The grading tools are handy at times, however these errors seem to happen later so I recommend "dumbing them down" to remove interactions before moving on to other tasks. Further to this I also avoid crossing feature lines (within same site), or when I do I ensure I insert a PI which seems to help. 

 
Yes, @Anonymous have gotten a little better, never let them touch another grading object, and never select the entire feature line.

[vaughan.giles7AGEV]

Thanks for your confirmations fine folk.

What annoys me greatly is that Autodesk have known about this in-built issue for many, many years and refuse to do anything about it.

[Anonymous]

I can say for sure if that was the case. I do know that it started happening when we created our own feature lines.We have stoped using the custom feature lines and started using the feature lines that c3d provides, we have not had any problems sinse switching.
My guess is that something in the process of creating the feature lines caused them to easily corrupt later down the road.

[Anonymous]

I find the issue occurs when I need to replace a feature line link corridor, for example when an offset center island shifts, i just recreate the feature and associate it.  And then the drawing deletes the feature lines.   

[jameshitt]

Classic inexplicable feature line behavior when using feature lines as corridor baselines and/or targets.

[vaughan.giles7AGEV]

If only they fixed this in-built issue.

[jameshitt]

They haven't fixed it because, well, they don't really have to. We're all locked in because the industry is all in with Civil 3D, and they have patents on their software ensuring that no one can create something better to compete with them. So they could fix it, and I'm sure if it wasn't as difficult problem as it apparently is, they would. But, at the end of the day, they can't seem to find an easy fix, so what do they care? We're stuck with their half-baked application, and they won't even bother owning up to its problems. Classic Autodesk.

[TimYarris]

Hi folks,

We have been following and researching this issue for quite a while. As has been mentioned in this thread, it is not an easy fix, primarily because  we haven't been able to consistently reproduce the issue. 

In the coming weeks, one of our development teams is going to further focus their efforts on this issue. Judging by the helpful comments on this and other threads, we should focus on a few areas:

• differences between DWTs created from acad.dwt and the Civil 3D NCS templates
• feature lines as corridor baselines
• use of feature lines in sites

To help us nail this down, would anyone please be able to provide:

• Steps they've used to consistently reproduce the issue.
• A video of the behavior.
• A dataset we could use for reproducing the issue and testing any resolution.

We sincerely want to fix this issue. If you would be able to provide any of the above assets to us, it would be incredibly helpful.

[C3D_TomR]

@TimYarris, I can’t duplicate the issue yet, but past history has shown that using the UNDO command on feature lines will at some point cause FLs to disappear. It’s typically a delayed reaction and not noticed immediately after the undo command is used to restore deleted FLs. When the drawing is saved and closed, the thumbnail preview the next morning will show the FLs but when the drawing is opened, the FLs aren't there. This may have only been an issue with acad.dwt vs NCS template. 

[jameshitt]

Thank you for the update, Tim.

Unfortunately, I no longer have access to the last project that this occurred on, and I've since completely forbidden myself from ever using feature lines as baselines again. I think I will try to duplicate it again myself with the same template as that project (which I do still have).

Edit:

C3D_TomR's comment above is absolutely correct. When editing feature lines, e.g. joining features, creating gradings on features, etc., using UNDO for these tasks has a very high likelihood of making the feature lines disappear with no way to recover them. It definitely has the feel that it could be directly related to the other cases where feature lines are disappearing.

[TimYarris]

Thanks for the tip regarding Undo, @C3D_TomR and @jameshitt . We'll add that to the list of things to focus on as we troubleshoot this issue. 

[ODO18]

I have been meaning to try to recreate the issue with 2021 to see if it is worth our Company going to 2021 yet.  When I do that I will share the drawing.  In the meantime the error is easy to reacreate (from memory):

1. Create feature line either by drawing or creation from object.
2. Create corridor and assign feature line as base geometry.
3. Assign curbing subassembly to feature line and create surface.
4. Edit the feature line in any way.  I.e. create or delete pvi or elevation point, move pvi at all, filled or any geometry modification at all.
5. Save and close drawing. 
6. Reopen and feature lines are gone.
7. Sometimes you may need to close and reopen a few times or just run an audit and that will guarantee the error to happen.  In fact that is why as a company policy we now have all grading in its own dwg base that we data reference into the main drawing, because audits cause errors in grading all the time even without corridor grading.  We do not run audits on our surface dwgs.

[Anonymous]

@ODO18  & @TimYarris 
As I've indicated before. This disappearing feature line issue does note require a corridor. I've never used a FL as a baseline. However, your other points about editing FLs having some influence over when they disappear seems to be valid. My co-workers and I agree it's FL's that interact with any other objects (Grading objects or other FLs) and then attempting to edit them, often causes errors... and then when the file is saved, closed, and re-opened... then sometimes (not always), the FLs disappear on the reopened dwg. We still use FL's... just avoid crossing (interacting) FLs at all costs until AutoDesk fixes this issue. 

Good to know about the audits having influence in re-creation of FLs disappearing. 

Cheers.

[ODO18]

I have not had the issue of disappearing feature lines outside of using them as corridors.  Also when I have used them as corridors they are not crossing or interacting with any other feature lines.

As far as issues you are having with them disappearing when they interact.  I always put a PVI at the intersection of two feature lines.  So no two feature lines are ever beginning, ending, or crossing each other without a shared pvi on all lines at that point.  Not sure if that helps, but that is what I do and have not had the issue.

Thanks

[TimYarris]

Hi everyone,

We're finally able to consistently reproduce this issue using the following workflow. We've validated this in both Civil 3D 2020.4 and 2021.1.

1. Create a new drawing in Civil 3D.
   It turns out we don't have to create from acad.dwt, an NCS Civil drawing can also do the trick.
2. Create a named feature line in Site 1.
   The feature line must have a name to act as baseline in next step.
   The feature line must NOT be site-less, or the defect may not present itself.
3. Create a corridor, using the feature line as a baseline. 
   The corridor can consist of an empty region with no assembly applied.
   You can also use an assembly in a corridor region, but it's not necessary to reproduce the issue.
4. Move the feature line (select it and MOVE).
   Note the corridor is now marked as out-of-date, but you can leave it alone.
5. Save the drawing, close it, and reopen it.
6. Delete the corridor (from within Prospector).
   You don't have to rebuild it before deleting.
7. In Prospector, check Sites > Site 1 > Feature Lines.
   The feature line is gone.
8. In Model space, select the feature line.
   Notice it doesn't have any PIs or elevation points.
   You can also see its Properties are blank.
9. Save the drawing, close it, then reopen it.
   The feature line is gone from Model space.
   If you do a Ctrl + A and LIST, you'll see that there are two transient feature line definitions somewhere in memory.

If anyone else has anything else to add to that workflow (or other workflows we can use to consistently reproduce the issue), we'd appreciate any other clues. Now that we can reproduce it consistently, it should help us isolate the issue.

Thanks very much for your patience and the details you've all provided to date.

[fcernst]

Hi Tim,

This sounds like it involves Deleting a Corridor to make the featureline disappear....?

What about all the "ghost" Corridor examples I sent you where there is still a Corridor, but the Baseline featurelines are all gone?

I rarely have to Delete a Corridor in my workflows, so the problem was especially conspicuous and frustrating. I then eventually came up with going with the Siteless option with better results, but still could get the behavior I describe, just less frequently.

Thanks for allocating development resources towards this now..