How to modify Eta and XoC of a FEA_POLY_SPAR via API?

[aschrist]

Good Afternoon,

I’m working with the OpenVSP API to create FEA structures for a wing, and I am able to add a polyspar using the following code:

front_spar = vsp.AddFeaPart(wing_id, fea_struct, vsp.FEA_POLY_SPAR)

However, I’m having trouble modifying its position. I tried using:

vsp.SetParmValUpdate(front_spar, "RelCenterLocation", "FeaPart", 0.5)

but this does not seem to have any effect.

What I would like to do is control the Eta and XoC of the polyspar points, similar to how it can be defined in the GUI.

In addition, in the GUI the polyspar currently has two points (start and end). I would like to add an additional point near the midsection (e.g., at section 2) and control its  Eta  and  XoC  via the API. I have attached an image where I manually added the additional (mid) point for reference.

How can I access and modify the Eta and XoC values for FEA polyspar points through the API, and how can I add and modify additional points?

Thanks in advance for any help!