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Smarter Corridors for Stream Restoration

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Message 1 of 24
tenmaryjan
6885 Views, 23 Replies

Smarter Corridors for Stream Restoration

Hi Guys,

 

I am currently working on a Stream Restoration project and am really struggling to find a flexible solution for modelling natural river corridors.

My Landscape Architect has provided me with a set of 2d-Polylines representing the proposed river alignment as well as some embankment lines. (Spline.jpg)

 

My first attempt was to create a corridor with a cross-section consisting of some generic links targeting my polylines. Please see attachment (Corridor.jpg). Obviously it results in a total mess. So I tried splitting the corridor in multiple sub-corridors targeting different lines as suggested by Dana Probert in her class on Stream Restoration. (Corridor1.jpg) However, given the curvature of these lines, the corridor simply never works as expected. 

 

Question #1: is there any way to create a ‘smart subassembly’ which would prevent those bowties? Ideally I’d like it to be able to connect to subsequent vertices of the targeted line. Maybe the subassembly composer is capable of doing such magic tricks?

 

 

Since the corridor approach didn’t work I tried adding the Polylines as breaklines to a surface without any other definition. To assign some elevation data I converted them to Feature Lines. The original 2d-Polylines have been set to Fit -> Quadratic though and Civil 3d just refuses to accept them as they are. So I’d go splineedit -> convert to spline and then Flatten to convert them to Polylines back again.

 

This way I can convert my Polylines to Feature Lines, assign elevations in the elevation editor and add them to an empty surface. After playing around with the mid-ordinate distance and interpolation values I end up with something usable but difficult to manage (Surface feature line.jpg). The Flatten command converts my beautiful splines to a set of interconnected lines and arcs, which aren’t that easy to control. And for all this effort the resulting surface isn’t as smooth as expected (Object viewer.jpg).

 

 

Question #2: is there a way to convert splines to feature lines, or better yet – add splines as breaklines to a surface and derive their elevation from a profile?

 

 

My current solution to this problem is converting the 2d-Polylines to splines, and then back to Polylines via Splineedit. This way I get a Polyline with tons of straight but short segments. I convert them to feature lines, assign elevations and add as breaklines to the surface definition. The resulting surface is super smooth. It just isn’t easy to modify because of the amount of vertices that have to be moved to do any adjustments.

 

Question #3: Do you know of any better ways to approach this subject? All of the methods I’ve tried would have worked perfectly with a simple corridor. It’s the curvature that renders them useless.

 

 

23 REPLIES 23
Message 2 of 24
tenmaryjan
in reply to: tenmaryjan

Some missing attachments...

Message 3 of 24
AllenJessup
in reply to: tenmaryjan

Would something like THIS help you? You could also google Civil 3D corridor bow tie fix.

 

Allen Jessup



Allen Jessup
Engineering Specialist / CAD Manager

Message 4 of 24
jmayo-EE
in reply to: tenmaryjan

I have not had great luck using corridors for existing watercourses mostly due to varying widths, deflections, etc between CL and the banks. They're great with proposed channels with parallel banks and well defined transitions. That being said I typically use flines because I have them to start with.

 

As per #2 you are doing it the way I do it. The Flatten command will convert splined plines to plines. Convert to fline and weed. Get rid of as many verticies as you can without changing the channel. This is important for your performance. Fewer points in the surface is less processing time. The flatten command will create a large amount of verticies to maintain the splines path. Assign the know elv's and chuck them into your surface.

 

C3D will not accept splined objects as breaklines nor will they be converted directly to flines.

John Mayo

EESignature

Message 5 of 24
AllenJessup
in reply to: jmayo-EE

John,

 

Am I misunderstanding something. I believe that 2012 would use splines in a Surface.

http://beingcivil.typepad.com/my_weblog/2011/05/autocad-civil-3d-2012-preview-3d-splines-to-create-c...

 

Of did that work so poorly that they took it out of more recent releases?

 

Allen

 

I found Splines mentioned as breaklines in 2014 help.



Allen Jessup
Engineering Specialist / CAD Manager

Message 6 of 24
jmayo-EE
in reply to: AllenJessup

Wow. I COMPLEEEEETELY missed that new feature and awsome post from that awsome blog. 🙂

 

Unfortunately I am still programmed to remove all splines from all work. Now I'll never go creating splines for channels as this is a huge pain trying to grip edit the spline to the real shots but if someone delivers 3dsplines it would be a decent time saver.   

John Mayo

EESignature

Message 7 of 24
AllenJessup
in reply to: jmayo-EE

I wouldn't use splines either. But it was in the back of my head that they could be used. Google did the rest.

 

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 8 of 24
tenmaryjan
in reply to: AllenJessup

Allen, John,

thanks for your suggestions - I tried splitting the corridor in multiple regions and letting the TIN triangulate between them but with the complexity of the splines I would just end up with 500 regions per corridor that would intersect anyway.

 

I have found a solution to corridor bow ties, that suggests using a marked point subassembly and creating a surface from point links.

http://www.youtube.com/watch?v=KnvmCRDl_MM (the interesting part starts around 6:00)

 

It would probably work but for that I'd need to have 7 baselines in one corridor: one center line, and 3 lines per each slope. Each of the baselines would be using a simple subassembly with only a markedpoint. Am I correct?

 

This is cumbersome to set up, but would allow me to derive the elevation information from design profiles and change the geometry of the corridor in a relatively simple way. 

 

Regarding adding 3d-Splines as breaklines. My problem is that I only have 2d Splines and I want to be able to control the elevation in a profile view. With featurelines it is possible since I can project them into a profile view and grip edit them afterwards. Is there a way to do that with splines?

 

As I stated in my first post - I am looking for a flexible solution that would allow for easy and quick changes. We are in an early stage of the design process and need the model to respond to our needs.

 

@John: what I am dealing with now is the exact opposite of your experience. The existing channel is just a straight profile with a continuos cross-section, since we want the proposed one to meander and resemble nature as much as possible, we are running into the above problems.

Message 9 of 24
fcernst
in reply to: tenmaryjan

My vote is for Corridors.

 

 

Capture.JPG



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 10 of 24
tenmaryjan
in reply to: fcernst

Fred,

 

this looks very clean and simple! May I ask how have you built this corridor? It seems you are using 3 baselines, but how do you target them?

 

 

Message 11 of 24
fcernst
in reply to: tenmaryjan

Yes this is very clean and simple. This consists of one Corridor, one Region and one Assembly.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 12 of 24
tenmaryjan
in reply to: fcernst

Well that is great news. But what type of Assembly did you use to achieve this result?

 

If I were to guess, I'd say you are using 3 Baselines and one Assembly consisting of a single Marked Point for each of these Baselines. The Corridor Surface is than built using Point Codes. 

 

Am I correct?

Message 13 of 24
jmayo-EE
in reply to: tenmaryjan

That's my guess too but i also believe he might also be using an offset in the assembly for the banks to get perpindicular lines from CL to bank or vice versa. Not sure Fred only shows the tin surface and the cor FLines. That works pretty well as long as the bank doesn't expand to a lagoon or pond scenerio where parallel offset banks will exist.

John Mayo

EESignature

Message 14 of 24
sboon
in reply to: jmayo-EE

Here's my attempt at this.  I don't do this type of design normally, so my approach may be a little unusual.

 

Rather than using an alignment that winds around following the channel centerline I built one that approximates the middle of the proposed drainage and then used polylines and two profiles to define the channel bottom, the waterline, and the slope up to existing ground.

 


Clipboard01.png

Steve
Expert Elite Alumnus
Message 15 of 24
Neilw_05
in reply to: fcernst

I would expect very similar results if you generate featurelines from the alignments and used infills Fred. Have you considered that? The reason for using infills vs. just adding them as break lines is the triangulation should be more consistent between the bottom and top FL's. With breaklines the triangles would tend to form across the convex arcs. One downside is you'd have to close the ends of the FL's.


Not to say the corridor is not a good solution. Yours is remarkably well formed. Would you be willing to post your file for analysis?

 

With regard to splines and Civil 3D, it is important to note that splines cannot be used as breaklines but only as contours. At least that is the case through 2013.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 16 of 24
Neilw_05
in reply to: sboon

I'm looking at Steve's corridor vs. Fred's. The two approaches provide significantly different results. The slopes on Steve's tend to be orthogonal to the baseline whereas Fred's are more radial. This raises the question, which is the more "proper" result? How should slopes be measured in a scenario like this?

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 17 of 24
sboon
in reply to: Neilw_05

It may be that the difference in slopes is caused by the fact that Fred is using three breaklines across the surface where I am using six, and mine are somewhat more parallel.

 

Steve
Please use the Accept as Solution or Kudo buttons when appropriate

Steve
Expert Elite Alumnus
Message 18 of 24
Neilw_05
in reply to: sboon

Regardless of how the corridor is configured, I think the end result needs to be considered. What method will give the closest approximation to what will be built?

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 19 of 24
tenmaryjan
in reply to: sboon

Hi Steve,

 

thanks for your example. For a moment I thought you have just found a perfect solution to my problem. What I couldn't figure out however, was how the approximate Alignment would know on which side of the proposed centerline of the stream it actually is. It turns out it just doesn't. That is why at stages, where the Alignment is at the wrong side of the centerline, the Subassemblies just target back to it, which obviously causes some problems.

Corridor Surface.jpg

 

I have exagerated the profile elevations in your file to make it more visible.

 

Mariusz

 

Message 20 of 24
sboon
in reply to: tenmaryjan

Try this one instead.  The problem was the links from the assembly insertion point to the bottom of channel points.  They work fine when the alignment is in the middle but when it isn't you get links running below the side slope.  The solution was to hide those first two links, then use a LinkToMarkedPoint to make the connection between the two channel bottom lines.

 

I haven't tried it yet, but it seems like you could combine this assembly with the techniques used for intersections and culdesac design to create side channels, dead ended back channels, pools and ponds etc.

 

Steve
Please use the Accept as Solution or Kudo buttons when appropriate

Steve
Expert Elite Alumnus

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