Change beam Cross-section with C# script

Hi Clemens,

I was wondering whether it were possible to change a beam's cross-section using a script in karamba.

I want to use it to run a loop optimization within a custom component.

Thanks!

Lorenzo

Replies to This Discussion

Permalink Reply by Robert Naguschewski on December 14, 2016 at 1:39pm

Hey Lorenzo,

please have a look at the c# script component in the attached grasshopper definition where I assign a new cross section to the first element of the model. Please read the karamba 1.1.0 Hacker’s Essentials, in particular this sentence: "Before running your script in GH make sure to unhook the Memory load *.GHA assemblies using COFF byte arrays after typing GrasshopperDeveloperSettings in the Rhino text window."

Cheers,

Rob

Attachments:

karambaScript.gh, 16 KB

Permalink Reply by Lorenzo Greco on December 15, 2016 at 3:07am

Hi Robert,

Thanks for the script. I had already tried that approach but with a script that also analyzes the model and it seems not to update the crossection afterwards.

Attached is what I get.

Attachments:

Scripting_Update crsc_LG 001.gh, 28 KB

Permalink Reply by Robert Naguschewski on December 16, 2016 at 7:34am

Hi Lorenzo,

I understand the problem, but couldn't find a solution. I would also be happy if there were a solution by the Karamba team, I guess it's only one line of code where you update the model completely.

I added line 153 to your script and now the beam elements can refer to a cross section that is known to the model, but that doesn't solve the problem. It's interesting that the stresses are updated in the component whereas the displacements stay the same. When you disassemble and assemble the model again, the cross sections are updated correctly. I am confused...

Another problem I faced is the issue of changing the model upstream in the grasshopper definition. Cloning as discussed here doesn't solve this (http://www.grasshopper3d.com/group/karamba/forum/topics/scripting-s...).

Attachments:

Scripting_Updatecrsc_LG001.gh, 39 KB

Permalink Reply by Karamba3D on December 20, 2016 at 1:40am

Hi Lorenzo,

the two attached files show how to set up a custom cross section optimizer for beam elements. It should work with Karamba 1.2.2.

'DesignCroSecOpti.cs' contains the abstract base class for custom optimizers. 'DesignCroSecOpti_Simple.cs' shows how to use this in order to implement a simple optimizer.

The code was created in the course of the research project NFormations (see http://www.nformations.com/)

Best,

Clemens

Attachments: