Hi,
While deconstructing the shell from an existing FEM model, I noticed that the surface points are uniformly shifted by 0.176 m in the X and Y coordinates. Has anyone experienced this behavior, or can someone explain the possible cause? Please help
Would it be possible for you to share the FEM Design model and part of the script (the deconstruct part) ?
Personally I have never encountered this problem myself so far, but I am curious to see what happens 
Hi @AndreiM
Sure 
Please check the attached files.
I know it is generally better to start with direct Construct modelling. However, in my current task I need to explore multiple options such as different pile (support) locations, loadings etc which require updating the geometry each time, often due to lastâminute changes. This, in turn results in a large number of small FEM models. Therefore, I am trying a Deconstruct approach for a single model and trying to use GH.
Non Uniform Shell.str (1.5 MB)
CS2 Shell.gh (42.6 KB)
I donât know whats behind this but try to use the âCorrect Modelâ-command and merge all the region lines of your plates and I think youâll get the right coordinates:
Hey @Arun_N_Dinesh
I have looked at your FEM model, and when deconstructing the model the points are not shifted. See below:
The ââissueââ you are observing is the fact that your surface has more than 4 edges, therefore when using the component to get the control points of the Nurbs Surface this will return only 4 control points:
Therefore, it is just a matter of what you have modeled and how you want your model to work ( for example if you need to split an edge into a few sections).
I know that the difference between the Nurbs surface and a simple 2D surface may be confusing, but this is where the difference is in what you are observing.
For example see the plates below, where some are 4 sided and some are irregular. You can see what happens when trying to get the control points of the Nurbs surfaces:
I hope it makes sense what I was trying to explain
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@AndreiM
Thank you for Spotting that 
It turned out to be a NURBS surface control points issue
As you mentioned, the confusion between a NURBS surface and a simple 2D surface can be quite misleading.
Iâm still not entirely sure how and where the additional control points were added to what was supposed to be a simple rectangular shell element. Itâs possible that I accidentally introduced some midâpoints in between 
@MarcoPelle
I really wish FEMâDesign had an option to view shell point coordinates directly, for example:
Shell â Rightâclick â Properties â Show list of coordinates (in table format).
This would allow users to easily check geometry coordinate mismatches, verify the number of points, and perform an initial QA review of the model.
@AndreiM
Thanks again for helping me get back and resume with the workflow 
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