Fixing DOFs

[Corentin1985]

Hi,

Thanks for this very interesting Framat package.

It seems there is some kind of bug, or at least something I did not understand : when imposing boundary conditions at a node, fixing ux, uy or uz works well.

But I cannot fix any rotation : when I try to fix thx for instance, the keyword "thx" is not recognized ("KeyError : 'thx'").
In the code it seems it is called "tx" instead of "thx" so I tried "tx" but it does not work either ("fix value not allowed").

Can you investigate?
Best regards.