... . I'm investigating. cheers, Martin. posted: 17 May 2020 23:05 from: Martin Wynne Hi Jim, Why this particular radius/location should cause a problem not found elsewhere is proving difficult to track down. These things are usually caused by rounding effects -- somewhere in the maths will be a blindingly obvious explanation, but so far I haven't found it. However, the most important thing is that you get an error message about it, rather than nothing at all, so I have added this: 2_171750_090000000.png In this case, clicking try again does produce a result, although the V-crossing angles need a slight tweak (F9) to match the curves exactly. This will niggle me until I find it, but for now I'm going to leave it at this cop-out. Hopefully no-one will ever see it. In the next program update, thanks again for reporting it. cheers, Martin. posted: 18 May 2020 08:19 from: Jim Guthrie Martin, Many thanks. It looks as ...