Weird capacities on elements created with Karamba3d-scripting

Grasshopper Karamba3D
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Karamba_Component.txt (7.2 KB)

Hi!
I am working on my thesis, and as part of it, I am creating a Grasshopper plug-in that uses Karamba3D for structural analysis. For some reason, I’m getting extremely high utilization values on my elements, and the calculated capacities look very strange. I’ve uploaded a screenshot from Grasshopper showing these capacities, as well as a code snippet from Visual Studio where i create the elements . Do you have any idea how I can fix this issue?

2

Hi @Aleksander_Tybura,
could you send a small example definition where the problem occurs?
Which version of Karamba3D do you use?
Did you define the cross sections via a script?
– Clemens

3

Hi! My version of Karamba3D and KarambaCommon is 3.1.50129.0. I’m trying to write a script in Visual Studio that finds the best‐fitting cross‐section for my beams based on their utilization grade. However, I ran into an issue when checking the beam utilization in Grasshopper.

First, I used the “Beam View” component to check the stress/strength ratio (see the first picture), and then I used “Utilization of the Elements” (see the second picture). In both cases, the results were very high. On the third picture, you can see the detailed results from “Utilization of the Elements.”

When I created the same elements with the same cross‐sections inside the Grasshopper, I got much better results.

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4

Hi @Aleksander_Tybura, my first guesses would be that the issue might be related to incorrect physical units or that the generated cross sections haven’t been properly initialized.
Could you share a minimal example that reproduces the problem? If you’d prefer not to send the full script, it would be enough to internalize the resulting elements or cross sections that come out of the script.
– Clemens

5

Hi @cp1,

Thank you for your reply, and apologies for my delayed response. I discovered the reason why the capacities were incorrect. When defining the material class for steel S355, I mistakenly used MPa for the tensile strength instead of kN/m². After correcting this, everything now works as expected.

Thanks again for your time!