Not sure if this is a Survex Aven issue or an issue with the way Therion parses data to a *.3d file, or indeed whether it is because I’m using an old version of Aven. I was surveying fore-sight back-sight pairs, first time in a cave for ages... so initially made a naïve oversight: - forgot to make the backsight legs duplicate, thereby almost doubling the calculated cave length. In the entrance area of this (tourist) cave there is a big steel gate and overhead 240 v power wires some 15 – 20 m away. This led to 10-15 deg errors when outside the cave or some 4 m inside of the gate. We abandoned any hope of a compass survey outside the cave. Interestingly the powered-down cables in the cave seemed to have minimal if any effect on bearings. So I was using Aven to visually characterise the degree of misclosure on each fore-sight back-sight pair. ie Colour by error gave me nice dark blue 1x sd errors inside and lighter blue 3x sd errors near the entrance and outside. So far, so good. Then I realised that I needed to make the back-sight legs duplicate. But now Aven does not display the duplicate legs as being part of a loop, so I lose the very useful ability to quickly visualise all of the loops and their relative quality. In hindsight I have noticed that Aven misses plotting of loop closure sd of isolated legs for years, and I could not figure out why. I wonder if that is also related to a flags issue? And wondering if this is considered a bug? ie display of loop status by Aven should override Therion flags status (duplicate, approximate, surface etc) therion 6.1.8 (2023-06-14) Survex 1.4.1 > I’m using this cos the next version broke display of colour by error for Therion exported 3d files (I forget the reason now – maybe it’s been fixed since…) Regards Bruec