Rails is, primarily, a back end server side framework. Three.js is a front end library for rendering WebGL in a browser. They have little to do with each other. I think you're trying too hard.
The process is the same as adding something like jQuery, or any other javascript library.
- Drop the
three.js
file inapp/assets/javascripts/three.js
- Add
#= require three
to yourapplication.js.coffee
- Ensure that
javascript_include_tag('application')
is part of your application layout template
Now launch the server, load a page, and type THREE
in the javascript console. If you get a return value, your good! Now write some custom javascript, save it in app/assets/javascripts
and include it on the pages you want to do awesome 3D stuff.