Hi, I agree with Bruce, that it is really a very useful feature. I have just pushed it on GitHub (see commit 2ebc7ed).
The only problem is, that survex calculates error which "is the ratio of the observed misclosure to the theoretical one". I have implemented more simple export (it was much easier), currently therion .3d export contains error equal to 2 * relative error of a loop. (because of 0-12 aven fixed error scale). It should be possible to extract survex relative error from either thTMPDIR/data.err or data.3d file, but it will take some time.
But when I compared 3D files with relative loop error and error with survex ratio, I received two quite different pictures. Are these two measures not comparable? Is a relative error of a loop useless number? Has anybody tried to go to a cave and resurvey "red shots", whether they are really so bad?
S.