Regarding Implementation of n Image Rendering Web Service in Rails

Hello,

I have a number of legacy 3D and 2D rendering applications
(essentially batch applications) written in C++ that I now want to
expose as services on the Web. For example as a Facebook photo hacking
widget.

Can someone please suggest a pattern I should follow as the Rails
wrapper around my code. One of the issue is not having the app. block
on long running pixel crunching.

Cheers,
Doug