Bamboo Vierendeel Beam – continuity lost (64.3 KB)

In this beam concept there is an upper and a lower ”deck”. There, the elements should be continuous with no hinged connections. In between in the void, there are vertical crossing elements supporting the load from the upper deck and distributing it to the lower deck. I had to make separate line elements (see IDs) all over to make the line-to-beam function for all.

Now it seems the continuity in the upper and lower deck is gone, which is visible by the exaggerated load case. In real construction this is of course very bad. How do I make the continuity and keep all parts line-to-beam compatible?

I’m a newcomer and just an architect trying to learn structural engineering. Grateful for ideas,


Hi Ingemar,

sorry I cannot open your definition properly because of your extra plugins. Also, it is a bit difficult to understand your script. However when you simply input beams into Karamba3D, they are automatically set as rigid connections, not hinge connections. Therefore the continuity should remain, unless you specify hinges at these nodes.


Hi again,

I think I have got the continuity correct now, thanks for explanation. However, I’m not sure about the axial stress readout. I have not changed any colors and the blue for tension and red for compression don’t show up as indicated in the manual. The values coming out from the utilization component are not totally convincing either, with the max and min not appearing where expected. Should I use the Beam Set here?

As the gh file was hard to open I send here just pictures to describe the situation. Thanks for your attention,



you have set the render display settings to show on 0 to 30 and therefore you would not see an appropriate mapping of the stresses. If you set this back to 0 to 100% then this should be shown accurately

Hi again Matthew,

Thanks for further guidance. I got the colors right now and the stress read-out makes sense: Ranging from -11.1 Kn7CM2 (111 MPa tensile) to +10.3 (103 MPa compressive)

What strikes me though, if looking at the beam form below, is the clearcut change from blue to almost white as if the beam was not continuous.

Also, one would expect much more tensile stress and dark blue at the 45 degrees shear bracing at the ends of the beam. Did I miss something here after all?



Hi Ingemar, if you turn on the Nx (normal forces) in the section forces menu of the Beam View you can see the exact values of the forces in the beams and whether those members act in tension or compression.

Hi again Matthew,

I followed up your advice and it works! The numbers get stacked at some connections though, which is a pity because they could be very important to read. Is there a way to change the fonts, spacing or something to separate the numbers? The colors are also a bit confusing, for example the middle vertical element should be deep red as supposedly being compressed. Some elements are both red and blue.

Another observation: This beam is symmetrically designed, so are the supports and the distributed load. How come the forces are different at equal distances from the center and that they are not showing mirrored values?

Grateful for your continued support,


Normal forces Nx

Hi, sorry for the late reply. Can you upload a reduced version of your script so that we can take a look.

In regards to the text properties, you can adjust these in the karamba.ini file -

Hi again,

OK I opened the ini file, saved it as karamba_user.ini.


text height and offset of cross section force values at elements

crosec_force_text_offset = 40 #from 20#

Although I thought having admin rights the value was not changed, nor in the original ini file.

Question1: Was that the right thing to change for better visibility of force values? (better spacing)

Question2: How do I get permission to change the ini?

Question3: How do I tell the system to pick the k_user. Ini if I manage to change it?

Now for the other issue, “a reduced version of the gh-file”. I just have added some other plug-ins:

Lunchbox, Excelreadwrite, Ghexcel, Weaver, Bificals, Nudibranch, Brickbox 2, Silvereye

Should I uninstall some of those to make a reduced version, or how do I do it?



Hi, you can simply copy the file to another location, edit it there and then move it back to the original location.

Hi again,

OK changing the ini file works as you explained, thanks. But the offset value for force values which I changed from 20 to 40 did not help to avoid the stacking of numbers and the loss of readability on the graphics. Any other suggestion?

Also the mixing of colors red and blue is and the lack of symmetry (se previous) is are still mysterious.

Best, Ingemar

Hi, you cannot offset the text values which refer to the same points on the structure. With the Beam Forces component you can extract each value as a list on each beam and then display them yourself using the text tag component.

In regards to the symmetry, can you please share a simplified script - so that we can take a look.

Ok, Normal Forces to Text Tag fine, but that component also needs Location input (points) supposedly linked to the elements. I have tried to feed in from the elements output at Line-to-beam, but not accepted. How do you hook up the location input?

Now for the symmetry issue: How do I make a simplified gh-script? Should I uninstall the other plug-ins or save as XML? I don’t see an obvious way to do it.

Thanks, Ingemar

Hi, the location input is just a simple list of points on where you want to display the text. You can simply divide the line with the same number of segments as you have for the beam forces.

In regards to simplifying the script, there is no easy way. You will need to manually just clean it up and remove any additional components from other plugins. Otherwise it is difficult to troubleshoot your definitions.

Hi again, OK I think I will just make a new gh-file starting from scratch, being more rational now and come back later,
Thanks, Ingemar

Hi Matthew,

It has been a while but now I have finished the Double Decker Beam (Vierendeel) and all issues are resolved: Clear display of Normal Forces, perfect symmetry, and continuous beam elements. I really want to thank you for your endless patience answering all my questions!
PS: At the KTH, Stockholm (Civil Engineering University) two candidates have been studying the same project with ANSYS Mechanical software. It will be extremely interesting now to compare their results with Karamba!

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Hi @ingemar,

great to hear that you solved the issue! would love to see the results of your experiments!