Surface and Breaklines

[Vanslayer1]

As mentioned in my previous thread I am teaching myself how to use Civil3D. I think I now have the points basics figured out and am on to surfaces. I have created a surface using the points group I have imported from one of our previous surveys (10000pts). I am now onto breaklines and am confused.

 

1. Can I automatically connect points of the same raw desciptor to generate a breakline. (i.e. curbs, crowns, ditches)

 

2. How does breaklines work wiith tin data.

 

Could someone point me in the right direction. The tutorials provided import polylines already created.

[JerryG]

Hey Slayer,

I'm not sure about question #1. I'm sure there is a lisp out there that

someone has created that could draw a pline etc. from one desc to

another desc with the same block/point then you could

create a breakline from that line.

 

#2 Here is an explanation from the help file;

Breaklines force surface triangulation along the breakline preventing triangulation across the breakline.

Breaklines are critical to creating an accurate surface model because it is the interpolation of the data, not only the data itself, that determines the shape of the model.

NoteYou can add breaklines only to TIN surfaces.

 

Hope that helps!

[Vanslayer1]

So to create an accurate surface I must connect all of the raw descriptors (i.e. curb lines, centrelines, ditchlines, etc) with polylines. Once I have connected them all and developed my baseplan, I just add them as breaklines and the tin automatically adjusts the triangle to create the correct surface model?

[JerryG]

Yes and no.

You will still want to go in and adjust triangles by adding or deleting

them and run a Cleanup on the surface.

Also just connecting the points may not be enough based on how accurate your survey is. I will also click on the surface and

look at it often through "Object Viewer". This tells me if I need to adjust areas by adding or deleting traingles, breaklines etc. to get

a more accurate surface

 

If your dealing with a project of that size I would highly recommend

looking at other tutorials online. Autodesk's own website has some

pretty good ones also.

[Vanslayer1]

Thanks

 

It's about 2km with some serious vertical curve issues. It's already been done in LDD by someone else so I have a reference. Thanks for the advice.

[BIGAL]

Adding breaklines by automation ?

 

As I was looking at my bowl of spaggeti !

 

There is more to adding brealines to common codes or else you will end up with the line above. There are a lot of programs out there that do it generally directly from a total station so you end up with a string plan view. You can then in simple terms use say layers to nominate breaklines.

 

For stringing to work (could devote multipages here) you need to carefully code the points, in a simple form eg 01ROAD, 02ROAD the 01ROAD means join points with same code but never to 02ROAD etc

 

Our surveyor has say 15 years of computer total station surveying and has now come up with a system to simplify the whole Breakline and contourable point issues, our previous civil software was not as complicated you could set breakline yes or no in the code, in a nut shell a code descriptor is unique eg Edge of road will have two codes depending on situation,

"403" layer EDGE OF ROAD-B contourable and Breakline

"ER" Layer EDGE OF ROAD contourable and not a breakline.

 

I know this does not help but may make you aware of the problem of not carefully using codes in the field.

[rustysilo]

1. Can I automatically connect points of the same raw desciptor to generate a breakline. (i.e. curbs, crowns, ditches)

As BIGAL says, you can automate this, but it requires certain coding in the field.

If it has not been coded properly for automation and you find yourself doing them manually you can speed things up a bit by using the transparent commands. Draw a feature line and use 'pn (transparent for point number) which allows you to key-in the point numbers as opposed to clicking them. If you have a row of points that are numbered sequentially that you want to connect you can simply type 'pn > firstnumber-lastnumber and it will automatically connect them all, however you can't fully utilize this around a curve.

Another transparent you can use is 'po (for point object) which allows you to select any part of a point and it will snap to the node. I find this to be a pretty quick way to do it.

[Charles Roberts]

Here is a video of breaklines being added to better understand how they work:

 

[rustysilo]

This video does a good job demonstrating breaklines as well as SiteTopo.

 

How is it coming with the development Charles?

[Charles Roberts]

Still working on it...