Exporting connection forces from global FEM-Design model to reduced model [SOLVED]

Help C#
1

Hi there,

I’m trying to figure out a robust way to export connection forces from edges of selected wall elements in a global FEM-Design model, and then import those forces into a smaller, reduced design model where only the affected elements are kept and designed in detail.

My idea is essentially:

  • run the global model,
  • extract connection forces from specific wall edges (line/edge connections),
  • and re-apply those forces as line loads in a separate, stripped-down model that focuses only on those elements.

I’ve tried a few approaches already (via StruXML and manual data transfer), but I haven’t managed to get a workflow that is both reliable and supported by FEM-Design.

Importantly: I don’t want to use exported reactions — I specifically need to work with connection forces.

What would you recommend as the correct approach here?
Is this something that can be done via the FEM-Design API (or perhaps Grasshopper / scripting), or is it simply not supported in a clean way?

Any guidance on a best-practice workflow would be greatly appreciated.

Best regards,
Anders Nordlöf
Daily FEM-Design user

2

Hi @Anordlof !

The workflow that you are trying to solve can be solved with some scripting/automation. Do you know how to use Grasshopper?

3

Hi @MarcoPelle,

Thanks — good to hear that this workflow is achievable.

I wouldn’t say I master Grasshopper. I understand the concept and have tried it a few times during my studies, but I haven’t used it extensively in practice. Since I work in FEM-Design daily and increasingly feel the need for automation, this definitely sounds relevant.

From your perspective: would you consider a Grasshopper script for exporting and reapplying connection forces to be relatively straightforward to implement, assuming the user is at a beginner level in Grasshopper, but with a solid understanding of FEM-Design and structural modelling?

Best regards,
Anders

4

ehi @Anordlof

The task is a not an easy to start with but it is also true that we need to start somewhere :slight_smile:

template_line_connection_forces.gh (20.3 KB)

Have a look at the grasshopper script which might give you a good starting. If you are familiar with FEM-Design, you might be able to quickly grasp the concepts :slight_smile:

It is also suggested to have a quick look at the documentation page which quickly explain the basic tools.

5

Hi @Marco,

Thanks a lot for sharing the Grasshopper script — much appreciated!
I’ll have a look at it and start testing things out. With a bit of trial and error, I’m hoping I’ll eventually manage to get a working export/import of the connection forces.

Wish me luck — I have a feeling I might need it :slightly_smiling_face:

Best regards,
Anders

6

If you would like to take the challeng to perform the action using coding, you can start from an example that might be pretty close to what you are trying to achieve.

With AI coding assistant, it might be easier to use the tool in programming :slight_smile:

7

Nice — very cool to see a code-based example!

This is C#, right?

Do you think an AI coding assistant could realistically be helpful when working through something like this, or is the FEM-Design API domain knowledge the main bottleneck here?

Thanks again for pointing me to the example — much appreciated.

Best regards,

Anders

8

in my humble opinion, the AI coding assistant can realistically solve most of the issues related to modify/add/post process results. You need to set the environment in a way that the AI knows what to do and call.

Engineering judgement are still on the engineering side but performing the action can be delegated to the user,

However, your case study is not one of the easiest. If you achieve to solve the issue, you can solve all the other automation exercises.

10

Hi Marco,

Just a quick update: I actually managed to get exactly the workflow I was aiming for.

The tool now works as a standalone .exe. I simply double-click it, select the source .str file together with its corresponding results, make my choices in a dialog, and that is it. The selected connections, chosen connection force components, and chosen load cases are then extracted into a neatly packaged reduced StruXML file. The output StruXML is written to a folder in the same location as the .exe file.

I will upload the file as well, so please feel free to test it yourself if you like. The executable is bundled as a standalone application, so it should run without installing anything extra.

So far, Fx’, Fy’ and Fz’ behave exactly as I wanted. I have not yet tested Mx’, My’ and Mz’, so that part is still unverified.

And, honestly, I did not write a single line of code myself. GPT-5.4 did all the heavy lifting for me, after many hours of prompting.

Best regards,
Anders

1 Like
11

@Anordlof

that’s is amazing!

Would it be possible for you to share again the zip file?
You might be able to share it directly without wetransfer.

12

@MarcoPelle,

I’m uploading the ZIP file again via WeTransfer since it’s around 150 MB and too large to attach directly in the forum. It will be available there for about 7 days.

The ZIP contains:

  • ConnectionForceTransfer.exe – a standalone executable that performs the workflow I described earlier

  • Custom example – Connection force transfer NET8 test – the full project folder with all source code and supporting files, usable in Visual Studio or VS Code to build the executable

I should also mention that my experience of API-C# is VERY limited, so I really just have a small understanding about implementation details or how everything is structured in the code itself. However, the tool does produce the results I was aiming for.

https://we.tl/t-Yq1qyDon8nHBCoNG

Best regards,

Anders

1 Like