Creating Curved Cross Section, Bridge Engineering

Hey guys,

I want to model a curved bridge in Revit which is not the problem itself. But to create a longitudinal section is obviously not possible with Revit alone. Does anyone of you know, how a longitudinal section can be created with Dynamo? I was getting into the whole Dynamo thing by myself but don’t have a single clue how to solve this problem.

Thanks in advance.


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Hi, Benny! This is definitely possible in a number of ways, most of them involves using some form of Intersection method with the bridge producing lines you can further discretise to produce detail longitunal sections. However you probably have to give it a go yourself and come back here if you are stuck to get explicit help with your problem.

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Hello jostein_olsen,

thank you for your reply. I’ll try my best. It could take some time until I get the time for it.

I assume you are an engineer? Is this bridge curved in elevation or in plan view? Or both?
As Jostein said, there are many possible ways to do it, and even inside Revit (no need for Dynamo perhaps), but we need more information about the complexity of its geometry in order to help you better.

Can you provide some sketches of the bridge design you are aiming for?


Yes I am an engineer for bridge design. This bridge is only curved in plan view and my first project in Revit/Dynamo.
Further projects implicate bridges that are curved in elevation view and maybe have different types of cross section tilt which makes it even more challenging. But where there’s a will, there’s a way.

I didn’t find any solution to get “curved” sections in Revit. Is there any way to do that only with Revit itself?


edit: This project just started. I just want to figure out in advance as what kind of elements my model should be created that I don’t have to remodel it too often. So at the moment I don’t really have something to show you and unfortunately other projects require quite a lot of attention as well.

In Revit, a section is a rectilinear projection but can be broken down in a series of zig-zag fragments (‘Split Segment’). I don’t know how to perfectly follow the path of a curved bridge on a plan view without going in a zig-zag way I am afraid.

Now, if the problem is how to model curved beams, that’s easy, but you said that modelling is not a problem, right?

Hope this helps.

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You could split your bridge centre line into a series of chords, create a section at each chord, and finally place the sections next to each other on a sheet, to get a “developed section”.

In this case I snapped the sections together by their crop box, but I’m pretty sure you can create some custom logic that snaps them automatically.



If you just wanted a simple ‘profile’ view of the alignment (as opposed to a detailed section view) you could probably extract the chainage (ie distance along a curve) and elevation of edges or centrelines and then rebuild this into an elevation
I.e convert chainage to X


Thank you for your posts,

I’ll take a couple of tries and let you know in a while what I did.

Ok, Benny. Here is a quick example of the principle I’ve would have followed. Doing it with detail lines has it’s downsides of course since it is not a live updated longitunal section, but can probably be useful anyway.

The bridge:


Hello, something is maybe doable with the DynamoUnfold package (just an idea…)

Here is a very simple start for unfolding a face only curved in plan view. It could have been already discussed somewhere else but I didn’t find it. So, I have extracted external dimensions to recreate a surface on the XY plane and used UV’s for the placement of curves. All this sent to a drafting view seems to be accurate. But now, for an element curved in several direction, Z values must still be integrated somewhere…

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Hello Yna_Db,

Thank you for your post. I’ll try this for the start with a simple example as soon as I get some experimental time.

I discovered this AU Online Class recently:
There is a related package called Bridge to download, including a node called 17 UnrolledSection:

I did not test it yet but just thought it could be interesting to mention here…


Hi @Yna_Db, hi everyone,

I just tried the node “17_UnrolledSection” from Bridge package on a very simple objet (a curved slab)

But it crashed…
Anyone tried it as well and has the same feedback?
Maybe I am wrong somewhere but when I read the title of the node, I have the feeling it will facilitate the work!


No, I can’t make it work at the moment (calculation never ends) but I see that you could need to convert your curve into a spline. You can also double-click on the node to see how it is build.

@Dimitar_Venkov will there be any improvement to this?

Hi @Dimitar_Venkov,
I did almost the same script as You had shown us. In my case, planes are not perpendicular to the line:

Section-3.dyn (54.3 KB)
Any sugestion how to fix it?