Is it possible to use forms designed by Orbeon Form Builder into different xform engine

How to use the Orbeon Form builder designed form into different xForms engine.

I mean to ask, is it possible to export the forms designed using Orbeon forms as a single xhtml file without any Orbeon dependency?

No, this is not possible.

To qualify: you might be able to do it if you write (for example with XSLT) a transformation of the form definition produced by form builder to something else, but that would be a pretty big project in itself. So the short answer remains that no, this is not something you can expect to work, and it is probably better not to attempt it unless you really, really know what you are getting into.

-Erik