algorithmic modeling for Rhino

Here's a thread for questions and suggestions specific to the Geometry Gym addon to interact with SAP2000 Structural Analysis.  Note you can filter my blog for posts/examples specific to SAP 2000 using the tag cloud or this link here: 

First post relates to questions raised here:

SAP2000 uses slightly different terms to other structural analysis software (ie Load Patterns are  equivalent to Load Cases in most other software).  I am trying to do my best to ensure the GH plugin terminology matches, but still needs improving and this doesn't help with what connects to what.  If you spot something you think can be improved, please let me know.

I've attached my subtle changes to your GH def.  Note that at least one of the forces needs to be activated to true to get results to emit.

I had a request to report stress the other day, but when I went to check you can only extract the force using the API, so I need to find some time to do some additional coding to calculate these from the section properties.  Axial force you might be able to quickly calculate from the force using GH components.  

Note also I recently enabled the ability to nominate the SAP model units (ie Feet and kips) from a right click on the ssiBake button.  This should be done prior to the first exchange to SAP, so either save, close and restart Rhino, or disable the solver prior to first opening the model to make the change.

Hope it helps, look forward to hearing more.



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Replies to This Discussion

Hi Jeremy,

Sorry for the problems.  I've sent you an email.



Hi Jon, I've got a problem with the ggSAPConstraintLocal component; no matter what I supply to the Point input, it gives me an Invalid cast error, as shown below (using the create or find point component):

I can change the error by supplying other inappropriate data to P, but can't make it work. What's meant to go in here?

Hi Josef,

Constraints in SAP2000 seem to be allocated by group, so the input reflects this.  Attached is an example of diaphragm constraints, local are generated in a similar way.

Let me know if this doesn't help.




Thanks Jon, that worked perfectly!

Hi Jon/All,

I'm trying to use the GG components with mixed results.

Using the ggSAPsolver, I'm able to launch SAP and run the analysis however I'm struggling to extract results.

For instance, I've connected the ggSAPQueryNodeDisplacement into the Result Queries but the solver doesn't output any result.

What am I doing wrong?

I've flattened the inputs.

Hi Valerio,

Unfortunately there was an issue with the plugin, I have just updated all installer links with a new version on the downloads page at  Can you please update and let me know if it still doesn't work?



Hi Jon,

I'm building a parametric model with a seismic analysis.

When assessing the seismic load case, I don't find in the gg features a node corresponding

to a spectrum function definition. Is there any ?

Consequently, I've started the solver from a template including a spectrum function among those available in SAP 2000 .

It runs but without computing the seismic case. It seems the U1 factor in the load definition is not added

as per screenshot attached.

Here attached the sources and screenshot of SAP 2000 failing.

Anyone having the same issue ? Coud you help me on this ?










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