Hello All,
Structural Analysis for Dynamo currently does not support Volumetric elements in RSA. The only possible option for generation of solids in RSA via Dynamo is to create desired shape using simple analytical elements (like analytical panels and bars) and then to manually merge them into solids in RSA(for example by extruding analytical panels).
An alternative route to do it in a more automatic way is to use API outside of dynamo as described earlier in this post.
Kind Regards,
Maciej Kubica,
Software Engineer at Autodesk