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Crossing breaklines

13 REPLIES 13
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Message 1 of 14
gk
Enthusiast
4117 Views, 13 Replies

Crossing breaklines

When I try to add extra tin lines manually, I get the error message that my new line crossed a breakline at .........., and does not add my new line....but there aren't any breaklines defined in my surface.

 

I guess I could adjust the settings to 'allow crossing breaklines' but I don't know how that will affect my surface.

 

Any suggestions ?

 

Garry

GarryK
13 REPLIES 13
Message 2 of 14
john.mckenzie
in reply to: gk

If you are buidling your surface from contours and edges of rodways with elevation etc, you get the crossing breakline issue. the contours cross the roadway lines and create crossing breaklines all over the place.

 

So, depending upon how you are building the surface, you may want to allow crossing breaklines. It may be the only way to get the data in that you want.

Message 3 of 14
fcernst
in reply to: gk

but I don't know how that will affect my surface

 


It depends on what elevation option you choose to resolve the situation: First, Last or Average.

 

Generally, it's better to take a few steps back and resolve your data implementation approach,  and eliminate Crossing Breaklines.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 4 of 14
gk
Enthusiast
in reply to: fcernst

Agreed .... I Just don't know where to start, since there are no
breaklines defined in the surface....no figures or other lines or
boundary either.
There seems to be one area in the drawing where the contours and not
showing up and this is the area where I cannot add any tin lines.
GarryK
Message 5 of 14
john.mckenzie
in reply to: gk

can you give us a brief description of how this surface is created?

 

For example.

 

Add points

define outer boundary

swap tin lines

 

holes are appearing.

 

OR

 

start design surface 1

paste design surface 2

paste corridor surface

 

many ways to build a surface and each have their own inherent idiosyncrasies

Message 6 of 14
gk
Enthusiast
in reply to: gk

It was built by using point groups only, however, I have done considerable editing of the surface.......by adding or deleting tin lines.

GarryK
Message 7 of 14
john.mckenzie
in reply to: gk

deleting interior tin lines can cause many issues. Those deletion edits are creating the holes in your tin and oftentimes you cannot get the tin back with addtinline. See this thread and check and see if any of it helps.

 

http://forums.autodesk.com/t5/AutoCAD-Civil-3D/a-hole-in-my-surface/td-p/2135129

 

Message 8 of 14

I found a thread where a crossing brakline error was reported and no breaklines were known to exist. not sure why you are getting this message and the other thread I found provided no solution either for a similar predicament. I am baffled by that.

Message 9 of 14
jmayo-EE
in reply to: gk

If you are trying to recreate a surface built from an aerial topo and you have the typical dataset of acad points, contours and breaklines you may want to limit the surface definition to the points and contours only.

John Mayo

EESignature

Message 10 of 14
gk
Enthusiast
in reply to: john.mckenzie

Thanks John. The comments by Dana in the thread you pointed me to seem to fit my situation exactly.

From now on I will 'Add Lines' only and let the software rearrange the lines accordingly.

Thanks, again.

 

Garry

GarryK
Message 11 of 14
john.mckenzie
in reply to: gk

you can use the add line functionality without deleting the lines already there. It works like a mass swap edge command. It treats the line yuo want added as if it were a breakline and then swaps all the necessary edges to conform. this will avoid the "black holes" that occur when deleting interior tin lines.

Message 12 of 14
fcernst
in reply to: gk

From now on I will 'Add Lines' only...

 

Whoa, step back!  Too extreme....this is kind of subtle now....

 

That's not what she's saying. She suggests deleting surface points rather than deleting surface lines. Deleting surface lines creates holes.

 

Deleting surface points causes re-triangulation and does not create holes. 

 

I like the one person's suggestion of placing a surface point just to get triangulation going over the hole, and the deleting the surface point.

 

 

 

 



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 13 of 14
fcernst
in reply to: jmayo-EE

"you may want to limit the surface definition to the points and contours only."

 

This approach typically does not allow the new surface to sucessfully emulate the V-shape of the contours in drainages, nor the depict the correct longitudinal slopes of the drainages provided by the breaklines.

 

Perhaps try adding the points and breakilnes first, then add the contours as breakilnes. Then choose to Allow Crossing Breaklines with the option Last selected.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 14 of 14
jmayo-EE
in reply to: fcernst

Hey Fred. With field shot data things are different because the data is much more accurate. In these cases I agree the build order and I would never exclude breaklines. When dealing with aerial topo pavement breaklines rarely match contour elevation in my experience (I think that is the issue in this post) and rarely do I see a well defined crown in these contours. We also have bld outlines at roof elevation and other things to deal with like the fact that it will never match the original perfectly and it's most likely not accurate enough to build with (at least in our area). In that case, for my purposes, I want my new contours to be smack on with the source. My map will match their map. I don't want anyone asking why contours are different. So with the points and contour only method I get a great match in less than 5 min almost every time. The last thing I want my staff to do is spend 1/2 a day fixing work that was already completed by others.

John Mayo

EESignature

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