Documents can be complicated, what with geometry, rendering materials, blocks, user data, etc. So the best approach is to make sure all the document’s have been serialized to disk. Then choose one as the “main” document and import the others into is. Scripting Rhino’s Import is your best bet to ensure nothing is skipped.
It’s a good input. In my case i just need the geometry.
But would the other approach be to:
a) Get the Array of documents.
b) Get the object tables for each document.
c) Make some copy in the active document.