HI Therion friends, I'm working on a dataset with a friend, We have survex and Therion working independently, but putting the aven models [.3d] from the survex dataset and the therion dataset side-by-side we're coming out with differences. We nailed the x/y difference down somewhat with the magnetic corrections in the .th file due to dates. But we're now left with a difference in the height/altitude between the two models. The cave is a single entrance cave which is higher at the end (with a streamway 260-340m below), All of the differences are weird but the weirdest difference in altitude is in the middle, where there's a 60m difference in the survex/therion models, however further on at stream level, there is only a 20m difference [665 - 685] ##### The models are kept at: Survex: http://cave-registry.org.uk/svn/Andara/Tresviso/ Therion: http://cave-registry.org.uk/svn/Andara/Tresviso/Nacimiento/therion/Nacimient... run therion using Nacimiento2020_master.thconfig ##### I sent the following message to my friend to describe the issue: # "Hmm, I think the next thing to try and crack is the elevations. as I think there’s something going awry there, which might point us further towards the remaining 50m in n-s separation. On the .3d file generated from therion I get the following Entrance= 470m Dr2000stream_pina.23038= 665.30m Terror_firma.6= 933.34m On survex model I get: Entrance= 480m Dr2000_streamway2.23038= 685.26 Terror_firma2.6= 1025.53 I really can’t answer the 10m diff at entrance, the 20m difference at stream level or 92m difference at the top. Extrapolating down, Jurassic highway.0 is still 90m separation. However, satan_dr2000.1202 is 41m separation (higher in survex). Increases again to 66m sep at garden Eden.16 vs consort_climax.16E" If anyone can give me some help I would be thankful, as i'm confused! Regards, Alastair Gott.