Error : Kiwi 3D cannot refine periodic surface. Refinement. u is set to 1

Plug Ins Kiwi
#1

I am getting following error while assigning surface refinement to the shell element to the baked geometry.

error : Kiwi 3D cannot refine periodic surface.

Where as when I am assigning the same berp and surface refinement (without baking) to the shell element showing following error.

Solution exception: Object reference not set to an instance of an object.

How to solve the errors ?
ROOF KIWI 3D.gh (28.3 KB)

Please find the attached file. I am new to paramteric structures, hope so you won’t mind my silly questions. Awaiting your response & thanking in advance

#2

Hey,

I don’t have time to look at your file today but here’s a short hint: you could try to make your structure nonperiodic. There is a command in Rhino, most probably also in Grasshopper.

#3

Thanks it works but what’s the solution for the another error which I get while assigning berp a shell element.

#4

If it is the same error as in the initial file, you cannot input null objects into the shell component. You have to filter them.

#5

there is afaik no native component for makenonperiodic in GH but you can use e.g. a c# component with the following code:
private void RunScript(Surface N, ref object A)
{

var nurbs = N.ToNurbsSurface();

if (nurbs.IsPeriodic(0) )
{
  nurbs.KnotsU.InsertKnot(nurbs.KnotsU[nurbs.Degree(0) - 1], nurbs.Degree(0));
  nurbs.KnotsU.InsertKnot(nurbs.KnotsU[nurbs.KnotsU.Count - nurbs.Degree(0)], nurbs.Degree(0));
}

if (nurbs.IsPeriodic(1) )
{
  nurbs.KnotsV.InsertKnot(nurbs.KnotsV[nurbs.Degree(1) - 1], nurbs.Degree(1));
  nurbs.KnotsV.InsertKnot(nurbs.KnotsV[nurbs.KnotsV.Count - nurbs.Degree(1)], nurbs.Degree(1));
}
A = nurbs;

}

#6

Thank you so much Anna… It’s working…

I have one more doubt, can the analysis of whole structure (in this particular case, cable, shell, beam, column) can be done by using single command (linear & no linear analysis & IGA solver) or we have to analyse each component separately ?

Sorry to disturb you again :grimacing:

Thank you

#7

Not sure if I understand the question but yes you can (and should) do formfinding and structural analysis with the whole system.