Breaklines being ignored

[seattlesurvey]

I have added 3D polylines to my surface as breaklines.  The vast majority of these are being seen as bonafide breaklines by the TIN, in that they are not being crossed.  Several, however, are being crossed by TIN lines.

Why is this?

I have read that if two 3D polylines (breaklines) share a terminal point, they will be seen as 'crossing' and will be ignored during a surface build.  Is this true?  If so, how does one either fix this in the existing 3D linework, or generate contiguous 3D linework that can be used properly as breaklines?

Image below shows breaklines in yellow, TIN lines in orange:

Thanks for your input.

C3D 2011

E.208.N.0, Version 3

[Joe-Bouza]

I think I know what's going on here I used to get that a lot too. Try this: when you add the break line data check the box for supplementing distance and make it a reasonably small number 10 feet works well for me and your tin will be more uniform with out the added luggage of extra vertices

[seattlesurvey]

Thanks Joe.

I prefer to only use surveyed points as vertices in these 3D lines, thus I have not supplemented.  If that's the only way to get around this issue, I may do it.

Do you know why supplementing helped you in addressing this issue?  In other words - do you know what the heck is going on that makes this happen?  Thanks.

[fcernst]

You may want to check:

• The surface's Operation Type order.
• Use the Event Viewer to check for errors.

[seattlesurvey]

The event viewer does show lots of instances of crossing breaklines; when I zoom into these, they appear to be locations where 3D polylines share a vertex (meet).  The odd thing is that the breaklines do NOT appear to be crossed by TIN lines in these same areas (despite the event viewer message).  Breaklines ARE being crossed in other areas, per my original post - and these areas may well be being reported in the event viewer.

Generally when I build surfaces I address all of the crossing breakline errors I see in the event viewer, but when I saw the viewer reporting 'crossing' errors where 3D polys met, I didn't know how to address these (and so I haven't as of yet).

As far as the order of Operations, I have Point Group, various sets of Breaklines, an Outer Boundary, some Hide Boundaries.

Thank you for your suggestions.

[Jay_B]

Is a Survey Database being used? If these are Survey Figures take a look at the "use as breakline" check box and make sure they are checked accordingly.

[sboon]

Check the build options in the Properties dialog for your surface.  There should be a dropdown list of options for resolving crossing breaklines.  One of those options is to completely ignore both breaklines if they cross.  I'll bet that is what you're currently using.

[Joe-Bouza]

adding a suplimenting factor does not add vertices, it only tells cad to add more triangle along the breakline (at the breakline elevation for the suplimented point.) this would be particularly helpful on an arc. Also, if you are getting crossing errors due to shared points you should consider map cleaning the 3dpline prior to adding to the surface.

I dont know the algorithm but it does work. try it what do you have to loose?

[fcernst]

'crossing' errors

Ok, resolve those errors. The surface alogrithm is saying it is confused on what you want it to do at these locations. 

Use the Crossing Breakline Tool to examine each situation. Then give the specific direction to the surface algorithm how you want to handle it.

[dgordon]

try changing your build option for crossing breaklines to yes as I show in this picture.

[fcernst]

I would strongly advise against doing this and not truly resolving the issues. From a liabilty perspective.

Average elevation? What if they are significantly apart in elevation?

[seattlesurvey]

Thank you all for your input.  Responses:

Jay:  yes, I'm using a survey database, but I'm not using survey figures as breaklines - i'm using 3D polylines that I first generated by exploding my survey figures, then editing them after the fact as needed (removing bad elevations or dragging vertices to other nodes, etc).

Sboon: my 'Allow crossing breaklines' is set to 'No'.

Joe:  you suggest map cleaning the 3D polylines to avoid the crossing errors - would map clean address how two such plines meet?  Would this be a 'dissolve pseudo node' map clean action, for instance?

Fred:  I wasn't familiar with the crossing breaklines tool - trying to invoke it now, but C3D is slow in responding (this is a big surface with 59,000 triangles) ... okay, just got the panorama window listing breakline crossings ... will investigate!

Dan:  I prefer to not allow crossing breaklines and to resolve them as they are reported in the event viewer.  This time, though, there were so many, and they seemed to be mostly reported as crossing only because they shared a vertex with another breakline; I didn't know how to resolve that type of issue.

Thanks all.

[seattlesurvey]

Fred, that 'Resolve Crossing Breaklines" tool is very cool - much easier and clearer than zooming to the instances that show up in the event viewer after a surface build.  Thanks for that suggestion.

As far as my original issue (breaklines being ignored): those breaklines in question did not even show up in the list of 'crossing' breaklines I just spent the last couple of hours addressing.  Seems it's some other issue, and I can't say what it is.

Short of any resolution, I guess I will delete them and re-add them and see where that gets me.

It scares me, though, that there may be other breaklines in this surface being similarly ignored, and it's just that I haven't come across them yet.

[fcernst]

So you have no errors now?

Are you sure there are no Operations after the breaklines?

[seattlesurvey]

The operations I have below the 'Add breakline' operations are boundary adds and swap edge surface edits. 

Interestingly, I do still have some crossing breakline errors that show up in the event viewer, though these do NOT appear when I invoke the 'Resolve crossing breaklines' tool (I have resolved all of the latter).  I have zoomed to all of the event viewer errors, and none of them are in the area of my problematic (ignored) breaklines.

[fcernst]

Toggle off those surface edits and see what happens.

[fcernst]

To clarify:

1. To diagnose the problem, you do not want to have any Operations occurring after the breaklines are processed. you can just toggle the Operations off and you won't lose them, they will still be referenced there for later use.
2. You want to resolve all of those errors, because any errors can cause a host of undesirable issues with the surface.

[seattlesurvey]

Thanks Fred.  After my last post I had simply deleted the 3D polylines that I had used to create the original (ignored) breaklines.  My newly created plines as breaklines ended up working.

As it happened, there were also four crossing errors I wasn't able to resolve; after I toggle off everything below the breakline adds in the surface definition, these same errors still appear, and when I zoom to them, I'm unable to find a crossing, and the TIN looks as it should (i.e. the breakline is being enforced) as well as do the contours. ?

[fcernst]

I wonder if those crossing errors are the breaklines crossing on themsleves with short segments or duplicate vertices you can not visually detect?

[C_William_Lee]

This thread helped me with similar problems I was having with breaklines in my surface.  The best I can tell sometimes Civil 3d thinks breaklines are crossing when they are not especially if they have been joined.  I think it has something with the elevation points not being entered consecutively.  Anyhow, when I explode my breaklines to lines, join them using the join command and then add these new plines to the surface the surface acknowledges them.