VPaint is an experimental vector graphics and, now as of version 1.5, animation editor based on the Vector Animation Complex. The new version was presented on SIGGRAPH 2015 currently going on in Los Angeles.
Materials from this year's conference are not available yet. In the meantime, you can check out presentation from SIGGRAPH 2014, where the ideas behind VPaint 1.0, were presented.
VPaint 1.5 will soon be available on rollApp for you to try.