From: Andy Buckley <andy@in...>  20070303 16:05:26

Hi, I've been writing a PyXbased library (http://projects.hepforge.org/pyfeyn/) which makes a lot of use of the coil deformer for arbitrary lines. For display reasons, it would be nice if I can offer a "3D" variant of the coil line, where the line isn't drawn for a short distance around one branch of its selfintersection, giving the impression that you're actually looking at a 3D coil. (It's hard to describe... maybe the examples in the tutorial PDF linked from http://www.feyndiagram.com will explain.) Any suggestions how I can get this effect? The obvious thing would be to know the line param values for the selfintersection and then to split the line and remove the segments around those points. But I don't know how to get those intersection parameters  the fact that it's a deformation of an arbitrary line means I can't use a standard regular parameterisation and I get a roughly infinite number of points if I actually ask the line for its intersection points with itself! Any bright ideas? :) Cheers, Andy PS. I think we can assume that the line that's been deformed doesn't itself selfinteract... so that's not a concern. 