Hi Devs, hi Maximilian, I have a wish for a new path effect – or a modified one, since it is quite similar to the Ruler effect (that's why I CCed Maximilian who wrote it). It should act like a ruler (i.e. draw lines perpendicular to the path in regular intervals), *but* their length should correspond to the curvature, showing how much the curve is bent (second derivative). Example image: http://granjow.net/uploads/bugs/curvature-normal.png For Bézier curves this could be done analytically, but I would wish it to be numerically (i.e. the derivative over some distance like 10 page pixels). The use case I have in mind is bow making, to visualize irregularities in how the bow bends. Best explained in an image, here in the first post: http://www.fletchers-corner.de/viewtopic.php?f=15&t=17924&start=75 But obviously that's not the only thing one could use it for :) Could you do this? It would be absolutely great (… at least for bowyers :D) to have this in Inkscape! Simon