Issue with Coupling Point Axis

Hello,

There seems to be an internal modelling problem in Kiwi!3D when trying to use several “Coupling Point Axis”.

I am working on the model of an active-bending gridshell. In the non-linear analysis model, I have defined :

  • Beam elements : Warp beams, Weft beams, Cross (for bracing) and Links (to connect the Warp beams with the Cross)
  • Supports : for Warp and Weft beams
  • Two sets of “Coupling Points Axis” : one creating scissor connection between Warp and Weft Beams, the other creating hinges between the Cross beams.

What makes me believe that the error is not from my side if the fact that depending on the order with which the elements are plugged-in, the analysis runs or not.

Config_Warp_Scissors Config_Warp_Hinges Config_Cross_Hinges Config_Cross_Scissors

  1. In the first configuration, the Warp beams are added before the Cross beams and the Scissor joints are used. In this setup, the analysis starts running.

  2. In the second configuration, the Warp beams are added before the Cross beams and the Hinges joints are used. In this setup, the analysis returns an error (problem of patch). It looks like it tries to assign the Hinges to the Warp beams and not to the Cross beams.

  3. In the third configuration, the Cross beams are added before the Warp beams and the Hinges joints are used. In this setup, the analysis starts running.

  4. In the fourth configuration, the Cross beams are added before the Warp beams and the Scissor joints are used. In this setup, the analysis returns an error (problem of patch).

Thank you in advance
Regards

Hey,
could you share your file (privately)? I need to have a look at it. Most probably it is a bug. The order of the elements affects the intersection process in order to find all couplings and assign them to the respective element. You could also try a smaller model tolerance in Rhino and rerun the script. This could eliminate a possible error in the intersection routine.