The Building Coder blog...
"One important Revit 2014 API highlight is the new custom exporter framework providing direct API access to the rendering output pipeline, including geometry and material properties."
Jeremy goes on to detail this powerful new functionality in the Revit 2014 API and presents two custom exporters that have already been developed using the new API functionality, one for XML and the other for Collada.
Jeremy's blog post is here.
Credit: Luke Johnson's What Revit Wants blog.