Question about zero length spring

I create a model like this. It can rotate. In horizontal direction, I make the angle increase and the displacement increases with the angle.

But in vertical direction, the displacement reduces with the angle going up.

So what’s wrong?

Hi @3057905022,

as mentioned in the email, please check your joint definitions. I believe your system is kinematic as all your members are defined as trusses and therefore the deformation shows strange results.

Truss? I don’t get the meaning, so what should I do for the scissor-like elements?

Hi Kylin,
could you post your definition?
Did you test whether you model has kinematic modes? You can check that with the EigenModes-component.
In the Karamba3D installation folders you will find under ‘…\Rhino 6\Plug-ins\Karamba\Examples\TestExamples\Zero_Length_Element’ the file ‘’ which shows how to simulate a scissor-structure. Maybe this helps.
– Clemens