it seems that the Node Properties node of the ETABS tab is not working properly or it is a classic user error of mine … might also be the case ;). This topic is not urgent and you can take a look at it, after 2.10 … aaah and for reference, I have used the latest release candidate 2.10 RC4.
I have tried it out with the according node of the structural tab and the node recognized the vertices of the surface as it should.
Get Surface as ETABS Element 2D.gh (19.8 KB)
For reference please find the gh script attached.