Interpolated Section using Parametric JSON

Hi All,
I’ve recently begun using JSONs to define my sections in Grasshopper/Rhino which is great for defining parametric sections. However, I’ve come across an issue when trying to interpolate between two parametric sections.

The interpolation fails due to the following error
" Conflicting interpolation instructions found at structural line 1001 (beam 1.
In the master cross section 1 there are #-variables in a formula.
Simultaneously a second cross section 2 was defined."

I think this is because the section definition contains parameters rather than fixed values. Has anyone come across this before and has a solution? Maybe somehow “fixing” the variables so Sofistik can interpolate.

A workaround I have found is actually defining the beams as axes and then using the “Axis Variable Distribution” to change the required variables to suit at each station (i.e. start and end). It is not an ideal solution though.

Any help much appreciated

Link to grasshopper file if it helps


Have you seen our online documentation for the section definition in the JSON format?

Best regards
Frederik Höller
Your SOFiSTiK Support Team

Hi Frederick,
Thanks for the reply.
I used that documentation to create the JSONs initially. The jsons themselves are working and create the section as intended. However, when a SLN is asked to interpolate between two sections that are defined by JSON, it fails to do so.

Is there anything I may have missed when creating the JSON parameters?

Hi Ravener,

i see your problem, therefore there is a switch in the context menu of the “ModifySection” component.
Just right-click the component and select “Output as non-parametric section”.
This will convert the section to a fixed one not containing any variables or expressions.

Kind regards


Thanks Emanuel - exactly what I was looking for.