LandXML and Clothoid

Is anybody seriously trying to understand how to import a landxml file and draw clothoid curves in Dynamo? I managed to import the xml and read all the data but still I’m struggling to find a solution to draw the spiral curves and the cubic curves based on these data.

Unless you want to compute the clothoid from scratch, I would suggest approximating using a parabola…only there’s no node to create a parabola…because Dynamos geometry engine is so basic. My suggestion therefore would be to stick with Grasshopper or Generative Components for a task like this.

I think that because of the way it’s described in the XML you have to compute it from scratch and then you can probably approximate it with a nurbs curve. Or at least this is the approach I can imagine.

Probably the best way is to compute from scratch…and that is a very difficult task :slight_smile:

I know :wink:


Did you manage to solve this problem? Im working om this exact problem now. Any insight would be greatly appreciated.

Yes, you can have a look to my AU class and download the handout

If you have any question, let me know.


“MEP modeling made easy” just doesn’t cut it for the content in that video! Thanks! :slight_smile:

You’re right! And I’m so sorry but I tried to put as much as I could!

I meant that as the biggest possible compliment. You literally give away how to translate clothoids into Dynamo Geometry among a range of other valuable insights! :wink: Again, huge thanks!


Thank you so much!

I will most certainly have a lot of questions, but it will take the better part of the Chirstmast holiday to wrap my head around all of this. With the late night help form @jostein_olsen i will reach my goal og bridge modelling by early next year :slight_smile:

Good luck!

May be help you!

I have solved this, but any extra insight is usefull. What package is used here?

This package is created by me. The clothoid is build by group points. I use a formula:

Current, it’s not complete. it covert for Alignment and profile (not cross section and sperelevation)

if it is usefull i will send the nodes for you to test.

Hi @dtloi83 is it possible for you to share the clothoid creation node?
Txt peter

Can you share the package that you develop to create spiral curve in Revit?
and share the logic how to do that?

Thank you in advance.

Hi Guys, some years later … just published a set of Clothoid components:


This handout(MEP Modeling Made Easy with Dynamo) helps me a lot on creating clothoid from landxml data. But I got a problem when there are two non-INF value for radius. My output with this case is not good but for the rest it’s really working. Is anybody knows a solution based on these data?