hey all i''m using attachment_fu to add ''documents'' (the attached class) to a forum post (in our app). It''s all working fine for a single document - on the new post page i just have a file_field which sets "post[document]", which calls my Post# document= method, which builds a document for that post: def document=(file) self.documents.build(:uploaded_data => file) end Then the post is saved and it''s all good. I thought it would be nice to be able to add multiple documents at once. So, instead of writing to "post[document]" in the form, i''m writing to "post[documents][]", and i get an array of files through. I then do this - def documents=(files) files.each{|file| self.document = file} end expecting that this would build three documents, and that when i saved the post then the documents would get created. However, i''m getting this error, when i try to do the Post.build(params[:post]) in the controller: Document(#-635202458) expected, got ActionController::UploadedTempfile(#-613987618) Is it the case that there''s some rails magic going on here, and we''re not really dealing with file objects after all, but a tempfile, of which there can only be one? (like in highlander) Or something else? Grateful for any guidance... max -- Posted via http://www.ruby-forum.com/.