A SIGGRAPH 2012 paper Position-Correcting Tools for 2D Digital Fabrication, by Alec Rivers, Ilan E. Moyer and Fredo Durand. The paper is available here: http://groups.csail.mit.edu/graphics/positioncorrectingtools/ That site also includes a mailing list where you can sign up to stay informed about a forthcoming commercial version of the position-correcting router.