Simply Helpful - Nested Routes - Form_for issue

ultra n00b here.

I'm trying to use partials (_form.rhtml) for editing items.

My schema is project has many thing1 and thing2.                      thing1 belogns to project and thing 2                      thing2 belongs to project and has many thing1

Whenever I edit a thing1 or a thing2, the app passes the project id instead of the local id. <% form_for @thing1 do |f| %>

which of course breaks my app.

if I put <% form_for :project, @thing2 do |f| %>

I then get "Routing Error

no route found to match "/actors/9;edit" with {:method=>:post}"

Anyone clue me in on what I'm doing wrong?