Problem of articulation and rigid joint at the junction of multiple beams

Hello developer, I have a little trouble in use, I want to make beam 03 and beam 04 a truss, beam 01 and beam 02 is a rigid whole, can freely rotate around beam 03, but in the program [joint agent] set the hinge point of beam 01 and beam 03, but can not be rigid with beam 02, resulting in beam 01 directly fell down. How do I get to where I want to be?

Hi, can you please share your definition so that we can look at what the issue might be. (34.6 KB)
Hi, this is one of my test files and the node definitions are grouped.

Hi @Darren5,
please internalize the curve-input. It is missing in the above file.
– Clemens (33.4 KB)
Hi, sorry, now I have internalized the curve-input.

The geometry in your definition looks different as compared to the above image. I added an ‘Eigenmodes’-component which makes it easier to see rigid body modes: (27.5 KB)

I am not sure whether I understood you correctly: beam03 and beam04 should be hinged at their ends (My, Mz = 0), beam01 and beam3 should be rigidly connected and be able to rotate about the axis direction of beam03. It that case you need to add a spring element. An example for this can be found in ‘ZeroLengthelement_Scissor’ in the karamba3D examples (‘C:\Program Files\Rhino 7\Plug-ins\Karamba\Examples\TestExamples\01_Model’ or similar).

– Clemens

I guess not, beam 01 and beam 02 should be integrated (a whole prefabricated beam), beam 03 is the lower chord of the truss, beam 04 is the belly bar, and the whole beam 01 and beam 02 can be rotated around the lower chord bar.

In this case use a zero length spring element between the parts that need to rotate with respect to each other.
– Clemens (73.2 KB)
I know the zero length spring element. But when I used it, it didn’t get the right result, it didn’t change at all.

If I read the definition you sent correctly, it is not necessary to place a zero-length spring. A hinge at element ‘1’ will do:

Here is the definition: I had to updat the View-components to version (75.3 KB)
I hope this helps.
– Clemens

Thanks, this case works fine, but setting up four or more rods at a node is still a bit complicated.